Fallout: New Vegas

If you're late in the game and don't want to start anew like I did, here are some tips. I had been working towards the Mr. House ending, and had already killed the majority of Caesar's Legion for fun. You only need to complete THREE of these in ONE play through to get the achievement.

For the record, unique weapons of the weapon type necessary to complete these achievements count. For example, Dinner Bell is a shotgun, and counts towards all GRA challenges that require a shotgun. Also, the Killing Blow is all that matters. You could weaken an opponent to 1-2 bars of HP with any weapon, and finish them off with the challenge weapon, and then still get credit.

Also, dismiss your partners, as they can screw you out of a challenge by taking the shot themselves.

Against All Tyrants::

***Kill ten named Legion members with Hunting Revolvers, Ranger Sequoias, Brush Guns, Service Rifles, Hunting Rifles, or Cowboy Repeaters.

PROS :: The weapons required for this challenge are fairly common, even in the late game.
CONS :: Highly limited number of named Legion members. Easy to screw yourself out of this one.

RECOMMENDED :: If you can go for this one and you have enough Legion alive (check the list below), by all means do this one. Not recommended for people attempting to do a Legion ending.

Acquiring the weapons required is fairly simple - NCR Veteran Rangers like to carry Ranger Sequoia, and you get one for free if you complete the Return to Sender quest and convince Chief Hanlon to commit suicide. I wager you could also simply kill him and take it. Otherwise, the majority of these weapons are purchasable from the Gun Runners.

The challenge will be impossible if you've already undertaken NCR quests which require you to kill Legion members or just gone on a killing spree against the Legion. For me, this challenge was impossible because I had already killed half of them just doing quests.

For the rest of you, there are only 17 named Legion members with names in the game, one of which is the final boss, and Alerio only appears if you killed Vulpes Inculta in Nipton. You can get credit for Vulpes Inculta AND Alerio, if you kill Vulpes in Nipton with a required weapon, and then kill Alerio when he shows up later, upon retrieving the Platinum Chip. Silus, the Legionaire held hostage in Camp McCarran, does not count because you cannot bring the required weapons inside his cell. Here are the valid targets' identities and locations ::

Captain Ronald Curtis - Camp McCarran (Insider for the monorail bomb quest, disappears if completed)
Dead Sea - Nelson (Inside a Barracks in Nelson)
Atticus - Caesar's Legion Safehouse (Only accessible if you are good enough with the Legion for the key)
Aurelius of Phoenix - Cottonwood Cove (Second floor of the HQ building)
Canyon Runner - Cottonwood Cove (Patrols the area outside)
Cursor Lucullus - Cottonwood Cove (The ferryman, moves to the Fort later)
Decanus Severus - Cottonwood Cove (Patrols the area outside)
Alerio - The Strip, Outside the Tops (Only shows up if you killed Vulpes, otherwise Vulpes does)
Gabban - Nipton (One of Vulpes' men)
Vulpes Inculta - Nipton/The Strip/The Fort (Kill Vulpes at Nipton to get Alerio to spawn later)
Karl - Red Rock Canyon (The Legion emissary at RRC, sleeps in the Longhouse. Can be killed by Papa Khan and friends in the Oh, My Papa quest)
Alexus - Techatticup Mine (Inside the Mine)
Antony, Caesar, Lucius, Otho - The Fort (Antony is inside the Fort, outside Caesar's tent. Caesar and Lucius are inside Caesar's tent. Otho is inside the Fort, by the arena.)
Legate Lanius - Final Boss (Non-Legion Endings)

As you can see, it's very easy to screw yourself out of this one if you, like me, didn't expect the challenges. However, in theory this is one of the easier ones to execute if it's available to you.

Armed For Bear::

***Kill 15 named NCR Rangers or commissioned officer (Lieutenant, Captain, Major, Colonel, General) with Machetes, Rippers, Chainsaws, Throwing Spears, or Ballistic Fists.)

PROS :: Since most people don't usually have a reason to kill these people, they're usually still available to most players. The weapons are easy to find. There are about 35 named NCR personnel.
CONS :: If you killed all of NCR, you're screwed out of this one.

RECOMMENDED :: If you have the NCR personnel alive, do this one. If you're good with Sneak Attack Criticals, even NCR ending characters can get this challenge done.

If you don't want to lose reputation with the NCR, you can pull off sneak attack criticals on these and escape with no loss to reputation. Machetes and Ballistic Fists can be found from Prime Legionairies and other Legion personnel in the Fort, and Ballistic Fists are incredible for Sneak Attack Critical kills even on low strength/melee skill plays. Otherwise, the Gun Runners tend to sell Rippers/Chainsaws or you can get a Chainsaw from Motor-Runner in Vault 3.

If you go to the Ranger Stations Alpha/Bravo/Charlie/Delta/Echo/Foxtrot, each has a Comm Officer and a named Ranger which you can assassinate. The only exception is Charlie, which only has one Comm Officer and he can get killed in a Legion Raid late game. If you kill all the named Ranger Station personnel, that is 11 towards your total, and you only need to kill four more. If Camp McCarran is still intact, you can find five named personnel there, unless you completed the Three-Card Bounty quest which will cause First Recon to move to Camp Forlorn Hope. Camp Forlorn Hope has Major Polatli in the main tent and the First Recon officers if they have moved there. Bitter Springs has 2 named officers, Helios has 1 standing outside the main entrance, and Novac has old Ranger Andy in one of the hotel bungalows. The Mojave Outpost also has three named personnel - two in the offices, one on the roof of the bar/barracks where you recruit Cass.

Crackerjack Timing
***Kill ten Mojave Wasteland Cazadors with Tin Grenades, Long Fuse Dynamite, and Time Bombs.

PROS :: Cazadors can be fought relatively common, and on demand at The Thorn.
CONS :: You have to fight Cazadors. The weapon selection is highly prohibitive and hard to get in the late game, or get specific perks.

RECOMMENDED :: Only if you just happen to have the means to get the weapons or have them already. Bring antivenoms, just in case.

This one is a pain, and I only recommend doing this one if you have absolutely no other choice. Tin Grenades require the Mad Bomber perk, 25 explosives skill, 1 tin can, 50 pistol powder, and 1 duct tape. Long-Fuse Dynamite is hard to find late game if you already savaged the Powder Gangers, and Time Bombs require 50 Explosives skill, 5 dynamite, 1 egg timer, 1 duct tape, and 1 scrap electronics.

If you've already screwed yourself out of the NCR and Legion killing challenges, you need to get AT LEAST 10 of either of these weapons, and find Cazadors. They can commonly be found in the vicinity of Jacobstown/Remnants Bunker, east of Helios ONE, or north of Goodsprings near the Powder Gangers' vault.

However, the best way to prevent a long search is to do the quests for Red Lucy at the Thorn until you're able to request the ability to fight Cazadors on demand.

If you do this, you can weaken the Cazador before the gate even opens and finish them off in VATS with the explosive, and repeat as desired. It is highly recommended that if you are going for this one to save before an attempt and after a successful one as to avoid having to farm up more of the explosives.

Deathclaw Pro Hunter

***Kill 5 adult Mojave Wasteland Deathclaws with .22 Pistols, Switchblades, Boxing Tape, Recharger Rifles, or Dynamite.

PROS :: Deathclaws can be fought on demand at the Thorn.

CONS :: These weapons are a pain to find in the late game. Deathclaws tend to tear you apart.

RECOMMENDED :: If you know what you're doing, this one can be a cinch, especially if you have Deathclaws to fight at the Thorn.

If you're going to be doing this one, by far the best way is to unlock the Deathclaw fight at the Thorn by completing Red Lucy's quests, and fighting them one on one. You can land sneak attack criticals with your normal weapons before the gate even opens, get them to low HP, and then finish them off with the weak weapon in VATS. Use whichever weapon out of the base list your character is most proficient with to prevent any unfortunate accidents.

If for whatever reason you can't go to the Thorn due to killing them all, Deathclaws spawn around the Quarry Junction, the Gypsum Train Yard, and south of Vault 3 near the mountains. However, it is much easier to fight them in a controlled environment.

Man-Machine Interface

***Kill 10 Mojave Wasteland Mr. Gutsys and Sentry Bots with Brass Knuckles, Spiked Knuckles, Tire Irons, and Lead Pipes.

PROS :: Robots are on a respawn timer at New Vegas Steel. The weapons are easy to find even at high level. Love and Hate count as Brass Knuckles.
CONS :: None, really.

RECOMMENDED :: If you can do this one, do this one.
This one is a breeze - first and foremost, there are a good amount of Sentries and Gutsies at the Crashed Vertibird east of the nuclear test site. If you need a pipe or knuckles, go fight some Fiends near Vault 3 and you're bound to come across some who are holding one.

Go to the Crashed Vertibird and weaken as many as you can, then go nuts in VATS swinging to finish them off with your melee weapon of choice. If you need more, go to New Vegas Steel, near Camp McCarran. Inside are three Mr. Steel, that count as Mr. Gutsy. They are on a three-day respawn timer, so use them to kill off any for your total remaining, and go to Goodsprings. Wait for 24 hours, 3 times, for a total of 72 hours, and return until you have all you need. If you are not strong enough to take on the Crashed Vertibird robots, you can also take some out in the REPCONN Headquarters. If you manage to make it to the top and shut down robot security, you can just go back for all the Gutsy inside while they are disabled and hit them until they explode, unable to defend themselves.

In short, I personally managed to acquire the Armed for Bear, Man-Machine Interface, and Pro Deathclaw Hunter challenges, and I hope this encourages any of you who are despairing about a late game save and having to do this again to not give up and go for the gold. It took me three hours total to get ALL challenge achievements, even at max level with the only quest left being the endgame.

Happy Challenge Hunting!

The following are all the three star challenges added to the game.

Against All Tyrants

Kill any named Legion members with Hunting Revolvers, Ranger Sequoias, Brush Guns, Service Rifles, Hunting Rifles, or Cowboy Repeaters. (10 required, note: These need to have unique names)

Armed For Bear

Kill any named NCR Ranger or commissioned officer (Lieutenant, Captain, Major, Colonel, General) with Machetes, Rippers, Chainsaws, Throwing Spears, or Ballistic Fists. (15 required, note: These need to have unique names)

Crackerjack Timing

Kill Mojave Wasteland Cazadores with Tin Grenades, Long Fuse Dynamite, and Time Bombs. (10 required, Tin Grenades require the Mad Bomber perk)

Deathclaw Pro Hunter

Kill adult Mojave Wasteland Deathclaws with .22 Pistols, Switchblades, Boxing Tape, Recharger Rifles, or Dynamite. (5 required)

Man-Machine Interface

Kill Mojave Wasteland Mr. Gutsys and Sentry Bots with Brass Knuckles, Spiked Knuckles, Tire Irons, and Lead Pipes. (10 required)

Not all Deathclaws count. Quarry Junction Deathclaws are the only ones that will count and Blind Deathclaws should count as I killed one and it contributed. However I've seen mixed reports on which Deathclaws work however.

For tips for killing Deathclaws easier try using Turbo or if you have Implant GRX so that you have more time to dodge.

There are three Gutsys that contribute inside New Vegas Steel. You could also visit the crashed vertibird or Helios One. I suggest using Love and Hate found in Bonnie Springs (http://fallout.wikia.com/wiki/Love_and_Hate) since it will contribute to Curios & Relics.

As for the last challenge I recommend saving your file and killing either all the named Legion or NCR members and then reload your save since the Cazador challenge is much too bothersome in my opinion. Weapons for either the Legion or NCR challenge can be found at Gun Runners.

Named members of the NCR and Legion can be found at the Ranger Stations, Camp Forlorn Hope, Camp McCarran, The Fort, and Cottonwood Cove.

Also for the Cazador Challenge BIG NME has suggested the following

Tips on your Cazador Challenge in three steps.
Required that you have cleared out Bonnie Springs of the Vipers, yet still make your way towards there are around 6-8 Cazadors on route.
1. Wear the Elite Riot Gear & Helmet.
2. Hot Key your Stimpack's & Save.
3. Start at the Tribal Village and make your way towards Bonnie Springs. let the Cazador Swam you and throw the required weapon at your feet. Press the hot key for stimpack and you'll have multi-kills.
Now I know I said three steps, but if you did not kill the Vipers at Bonnie Springs then you can make your way to Callville Bay and to the Boat house filled with Cazadors.
I had 9 Long Fuse Dynamite only needed 8.

BIG NME also suggests the following for the Deathclaws.

Now as for the Deathclaw there are plenty around the Junction 15 Railway Station, they all count towards the "Deathclaw Pro Hunter", some are young but are not much of anything, just a slight annoyance.

I started this at the end of the game and was still able to acomplish it. For this stratagy you will need the NCR.

** You might want to make a save if you go for Armed for bear if you dont want bad karma with the NCR. It does drop fast!

Challenges/Need
Man-Machine Interface; Brass Knuckles or Spiked Knuckles
Deathclaw Pro Hunter; Silenced .22 Pistol
Armed for Bear; Machete

1.) Man-Machine Interface: 10 needed
As RF117 has stated
Nellis Air Force base will have two Mister Gutsy (towards main entrance).
Nellis Array will have two more Mister Gutsy (As you fast travel there you should have no problem locating them).

-Use Brass Knuckles or Spiked Knuckles to kill the Mister Gutsy Robots.
-After you kill all four head over to any area of the map, and wait five days.
-Once the fifth day has passed head over to the Nellis Air Force base and Nellis Array to kill four more Mister Gutsy.
-Re-due till challenge is complete

2.)Deathclaw Pro Hunter: 5 needed
I killed all the Deathclaws, so I went to THE THORN where you can kill them in
an arena either 1 or 3 at a time. I simply shot 2-3 rockets at them and finished them off with the Silenced .22 Pistol. Just repeat till Challenge complete.

3.)Armed For Bear: 15 needed
*This requires named NCR Rangers or commissioned officers (Lieutenant, Captain, Major, Colonel, General)

I started with the smaller camps. Remember to kill the Named NCR with the machete, and the others you can use a gun. Might be handy to have stempacks and a Rocket launcher for the NCR Veterans and Heavy Gunners.

***NOTE If you have Miss Fortune or Mysterious Stranger they can pop up when using vats and that kill will not count.

If you kill rangers outside a building the ones on the inside wont know.. and vise-versa

Ranger Station Alpha has (2) Ranger Rebecca Lineholm and Comm Officer Castillo
Ranger Station Bravo has (2) Comm Officer Tiden and Ranger Ericsen
Ranger Station Charlie has (1) Comm Officer Stepinac
Ranger Station Delta has (2) Comm Officer Scheffer and Ranger Pason
Ranger Station Echo has (2)Comm Officer Green and Ranger Erasmus
Mojave Outpost has (3) Major Night, Ranger Chost, and Ranger Jackson
Camp McCarran has (4) Colonel James Hsu, Lieutenant Carrie Boyd, Lieutenant Gorobets, and Major Dhatri

Total = 16

2 tips for the challenges.

The deathclaw one, it has to be adults first of all, and what i did was shot them with rockets untill it was almost dead, any weapon really but make sure the final hit is with your fist or a silent pistol, it works as long as the last bit of health is taken off with the correct item.

The cazadore one, it says you have to kill them with a long fuse dynamite or a time bomb, this is wrong, as long as your holding that weapon when they die. if you have one time bomb and kill 4 with it it wont count as you are not holding one, if you have two bombs and use one and your still holding one when it blows up then the kills will counts but what i did was through a plasma/frag grenade at them quickly switched to holding a time bomb then the plasma grenade kills counted towards the amount as i was holding the correct weapon whey they died.

Hope this helps

Here is another tip that was useful to me on challenge - Deathclaw Pro Hunter.

The problem was - I killed all Deathclaws before i got the DLC.

So alternatively you can go to The Thorn and initiate a "greater challenge", you can battle 1 or 3 deathclaws, each of them counts towards the achievement.

To get the opportunity to fight deathclaws you have to do the quests for The Thorn first. In my case I have done them in past.

Hope this helps.

Here are some tips for Man-Machine Interface if you killed all Mister Gutsy at the Crashed Vertibird and Helios One.

Man-Machine Interface

*Nellis Air Force base will have two Mister Gutsy (towards main entrance).
*Nellis Array will have two more Mister Gutsy (As you fast travel there you should have no problem locating them)

-After you kill all four head over to any area of the map, and wait five days.
-Once the fifth day has passed head over to the Nellis Air Force base and Nellis Array to kill four more Mister Gutsy.
-Rinse and repeat as needed.

Hope this helps.

Cheers

This one isn't as bad as you think.. I got a fool proof guide here to get you this one pretty quickly, being that you kept a lot of saves along the way like I did.

Make sure to maybe load a file up that you had maybe before doing: The House Always Wins, Render Unto Caesar or For the Republic. And create a save before doing this.

The three quickest challenges are:

Against All Tyrants: Kill 10 named Legion of Caesar Guys with Hunting Revolvers, Ranger Sequoias, Brush Guns, Service Rifles, Hunting Rifles, or Cowboy Repeaters. I used the Hunting Rifle myself since my guy was really highly leveled with Guns.

There are 4 at the Fort: Caesar, Otho, Lucius, and Antony.. Otho and Antony were near the arena by the time I made it to the "drawbridge" part. And Lucius and Caesar are actually in the "tent to Caesar" part. Just fuck up Caesars' tent and you should be fine.

Then fast travel to "Cottonwood Cove". Then kill Canyon Runner, Cursor Lucullus, and Decanus Serverus outside of Cottonwood Cove. They're usually just outside patrolling around it. If you go in a house, they usually follow you. Just make sure to kill them off if you see the name. Then make your way to the HQ building then go up the stairs and take out Aurelius of Phoenix. He's on the top floor and then take his loot or don't. Doesn't matter too much, but he has the Legate Lanius headgear, which I think is pretty awesome. But I had the T-45b Power Armor.

Then fast travel to Red Rock Canyon, and come up in the "Longhouse," take one of the backrooms, I think to the left, then take out Karl. He was asleep when I got him, and if he is, the the rest of the people in the house don't take you out at all.

Then fast travel to Techatticup Mines. Go through there.. and the opposite way that "Anywhere I Wander" leads you, and take out Alexus. All of him and his men are weak so this should be easy.
By this point that should be 10 and the other 7 are pretty hard to get because it's easy to screw yourself out of. And Legate Lanius is a pain in the absolute ass to kill... and he's also the final boss, so you'd have to go all the way through the endgame and save him for last. But with those 10, that is enough for the achievement. If not, then feel free to look here for help http://fallout.wikia.com/wiki/Against_All_Tyrants. But many of the remaining 7 are easy to mess up.

Now do Armed for Bear:

Make sure to grab a chainsaw from Gun Runners.

Go to Camp McCarron. Go straight to the Terminal Building. When you first enter, go to the left door in front of you and get Ronald Curtis. Leave his office then take a right after leaving and go all the way down and get Colonel James Hsu. Then get Lieutenant Carrie Boyd. She's usually near the terminal area smoking a cigarette. At least that's how I got her. Then I went outside and got Major Dhatri. That should be enough for Camp McCarron. At least it was for me.

Then travel to Camp Forlorn Hope. Then go straight into the tent and get Major Polatli. He's the only one here. Then exit and kill off anyone bothering you, then fast travel to:

Ranger Station Alpha and get: Ranger Lineholm and Officer Castillo

Then go to Bravo and get: Officer Tilden and Ranger Ericsen

Don't worry with Charlie, by this point the guy that usually patrols this station is dead.

Then go to Delta and get Officer Schaeffer and Ranger Pason.

Then go to Echo and get Officer Green and Ranger Erasmus.

Then go to Foxtrot and get Officer Lenk and Ranger Kudlow. At this point, there should be 15, but if not then just look here for extra help http://fallout.wikia.com/wiki/Armed_For_Bear.

Then for Challenge three go Man-Machine Interface

Go to Bonnie Springs and kill off all the bad guys. On the viper gang leader, loot the Love and Hate knuckles http://fallout.wikia.com/wiki/Love_and_Hate.

Then fast travel to New Vegas Steel. Inside, there's usually a fiend, then kill all the Mr. Steels. (The Crazy Mr. Steel thing doesn't count). Each time you should get 3 credits. Then fast travel somewhere else, wait three days then travel back. You have to actually fast travel somewhere else then wait because I tried walking outside of New Vegas Steel and waiting 3 days then coming back and it didn't work til I actually fast traveled somewhere else, then waited, then traveled back to New Vegas Steel. More info can be found here . Repeat this a few times til you have 10.. Then viola! Achievement.

Many people complain about how Caesar's legion isn't enough because they're all killed off. If so, then do the Deathclaw Pro Hunter challenge.
Go to The Thorn and ask Red Lucy to battle a Deathclaw (and you can do this as many times as you want). Just weaken him down with any weapon you have then kill him off with a Recharge Rifle or a Switchblade. The Recharge Rifle is probably the easiest to get because you can either buy or steal one from Silver Rush, which is literally across the road from The Atomic Wrangler. Then just rinse and repeat for 5 times, since there are no limits to Red Lucy. If you can't battle a Deathclaw from talking to Red Lucy, then you'll have to do the "Bleed Me Dry" quest, but it's really easy.. Just kinda long, but worth it if you have to do the Deathclaw Pro Hunter challenge for the achievement.

If you have anymore questions feel free to message. I left the Cazadore challenge out because that one is just WAYYYY too hard and only for people really wanting a challenge. Because Cazadores are a bitch and a half, and they're honestly the worst enemy in the game, imo, because they attack in groups and their vemon knocks out so much of your health that it's not funny at all! This is ONLY reccommended if you screwed yourself outta the legion challenge AND the NCR challenge. Make sure to have anti-venom if you even attempt this challenge. Honestly, I would battles 1000 Deathclaws before I battled a group of Cazadores. They're literally the worst!

Then after the achievement bloops, then reload the save you made before. This is recommended so this NCR and legion don't hate you, which one or the other probably hates you anyway, but still, it beats having both hate you.

Deathclaw pro hunter method I used was go to the Junction 15 Railway Station. Find a deathclaw one at a time and lure them the station, crouch down, get under the deck of the station, and unleash the .22 pistol on it. It's to to tall to squeeze under the deck completely, and won't runaway either. You want to enter under it from the right side, if facing from the front. I worked well for me, every time I lured one there. Hope it helps.

All of them are very good suggestions. I summarised the best ideas and did it using the methods below.

I picked the following:

1. Crackerjack Timing
***Kill ten Mojave Wasteland Cazadors with Tin Grenades, Long Fuse Dynamite, and Time Bombs.

My solution:: You need a high DT level armor with high character level. I was level 50, had on the Elite Riot Gear from Lonesome Road, and also had the synthetic heart from Old World Blues (which gives poison immunity) and only ONE stick of long fuse dynamite (hot key to one of the weapon slot).

Proceed to Callville Bay, and Cazador Nest and throwing what ever explosive you are using at your feet as they swarm around you, then quickly switch to long fuse dynamite before the grenade explodes, and you will get credit for the kill.


2. Deathclaw Pro Hunter
***Kill 5 adult Mojave Wasteland Deathclaws with .22 Pistols, Switchblades, Boxing Tape, Recharger Rifles, or Dynamite.

You need a silenced .22 pistol, purchased from Gun Runner. Use the Thorn method if you have already unlocked it. Use the method below if you, like me, have not unlocked the thorn and find it too long and tedious.

I would recommend the Gypsum Trainyard. If you start from Raul's shack you can sneak up the hill without being detected. Bring Ed-E as your companion and ask it to wait at the bottom of the hill. From there you can safely and easily shoot the blind deathclaws using any weapons to weaken them and the silenced pistiol as the finisher for the challenge. Even if you did not kill the deathclaw in the first attempt, Ed-E will help to attack it when the deathclaw is near your location, giving you a second chance.


3. Man-Machine Interface
***Kill 10 Mojave Wasteland Mr. Gutsys and Sentry Bots with Brass Knuckles, Spiked Knuckles, Tire Irons, and Lead Pipes.

I used the Love and Hate found in Bonnie Springs. I went to the Crashed Vertibird, weaken them using other weapon, before finishing them using the me-lee weapon (This should net you 9 kills). If you need more, you can go inside New Vegas Steel. There are three Mr. Steel, that count as Mr. Gutsy. If you have difficulty defeating the robots at the crashed Vertibird, there is a Mister Gutsy that re-spawns in Nipton. It's inside a house that has a cow skull on the mailbox.

Just a tip for Deathclaw Pro Hunter - I fought them in the Thorn.

Save before you touch the cage door because the minute you touch it, the gate opens. As soon as the cage opens, run about half way toward the Deathclaw cage, drop a Satchel Charge and run back to your cage and have your trusty 22 pistol ready. When the cage opens for the Deathclaw, it always turns around and walks further into it's cage giving you time to plant the charge.

Normally, 1 charge will kill it, giving you the challenge message. Just rinse and repeat.

If I might add other tips:

1. Load up on stimpacks.
2. Get a LOT of antivenom, because if you don't, you're dead within the second.
(if you have a survival skill above 40, you can make LOTS of antivenom out of Night Stalker Blood and Scorpion glands) A lot of night stalkers can be found near the BoS safehouse (blood cave or something like that) Scorpion glands can be won at the Torn when you battle Giant Radscorpions for 3 to 4 glands each.
3. Obtain long fused dynamite by killing Powder Gangers and search the NCR correction facility.
4. Go to places with some Cazadores, like the wind park near Novac. There are, like, 8 of them. Stand there, program stimpaks to use and throw dynamite.
5. Another great place is the Bootleg Brewery (or something with that name) when you are close to 10 (I killed 7 Cazadores before reaching 10), and kept pressing for stimpaks. After some great explosions, the cheevo popped :D