Fallout 76

For this achievement you need to reach the "Ally" status with the Settlers located in Foundation

I recommend doing this specific achievement and his counterpart for ally the Raiders in separate characters, since the best outcome of reputation is earned by completing the main mission with that faction.
There is 7 Reputation status with each Faction: Hostile, Cautious, Neutral, Cooperative, Friendly, Neighborly, Ally.

At this point you should be around the Friendly Status so you need to grind around 2 or 3 more levels

How obtain Reputation Points when I finish the main story?

Daily: Vital Equipment You should press the option to donate your reward to Foundation in exchange for a little more reputation. (Faction Daily's give you around 20 XP and 5XP extra if you donate the reward at the end of the mission)

Daily: Photo opportunity You need to photography The Raiders base then bring the photos to the Foundation NPC in exhange of some reputation. You get this daily by talking to Davenport located in the Overseer House. (This Daily gives you 2 points of XP)

Daily Missions related to factions resets every day at 7pm EST

From Friendly to Neighborly status you need around 318XP, doing the Faction Daily 12.8 times will provide you enough XP to rank up, then you need 720XP to reach Ally from Neighborly

There's also random encounters where Settlers or Raiders are fighting off a random group of enemies (including the rival faction, pick a side). If you help them fight off the enemies, you can talk to one of the NPCs and get some rep. This is technically repeatable and not on a daily timer. Best place to do this is Marigold Pavilion. Doing this encounters will grand you just 1XP point so it's completly optional.

Okay for this achievement I have a little circuit that I complete daily that get quite a bit of XP without much hassle
-First off I spawn in at Marigold Pavillion just SW of vault 76, there is a random Faction vs Faction encounter here where sometimes you will have to help out the Settlers(not always settlers that spawn)
- I then fast travel to Slocums Joe just SE of Vault 76 where there is another FvsF Encounter
- I then do W C Aeries’ Solution and fast travel to Flatwoods quite far South of Vault 76, this is very random and might not always spawn or be and XP encounter
- I then travel to the Overseers house and pick up the daily photograph mission from Davenport, making sure to pick The Crater as my “target”,I complete the two photos and then I head to Foundation
- Once here I head to speak to Ward and accept his Daily Vital Equipment mission, and while here I hand in the Photos to him choosing not to take the caps
-I then complete the Vital Equipment quest and hand it into Ward by selecting to Donate my reward to Foundation(IMPORTANT: You Must let him finish talking and not skip his dialogue for it to give you the Xp)
- I then do the route in reverse, first heading to Davenport to finish the Photograph daily mission, then to Flatwoods again, then to Slocums Joe and finally back to Marigold Pavillion, completing each of their respective Enounters should they have respawned
- I then log off for the day ready to repeat the next
-Theoretically you could jump servers and repeat the three Encounter spots over and over but I find this tedious and would rather do it day to day
-Good luck and thanks for your patience reading this

Faction rep works on a scoring system in Fallout 76 based on "Rep points". Certain actions award points, completing side quests, completing the Wastelanders story line, assisting the faction when out in the wasteland etc.

There are 7 tiers of reputation that can be acquired for each faction. For this achievement you need to reach the top tier of reputation with the Foundation. (Ally status)

The number of points required to reach Ally status is 12,000.

Tier 1: Hostile (-2000 points)
Tier 2: Cautious (-1000 points)
Tier 3: Neutral (0 points)
Tier 4: Cooperative (1000 points)
Tier 5: Friendly (3000 points)
Tier 6: Neighbourly (6000 points)
Tier 7: Ally (12000 points)

My suggestion when aiming for ally status would be to first complete the main story with the Foundation and split the gold with them in the final mission. This will land you in Friendly territory as cumulatively you will acquire around 4000 points of rep with the foundation for doing this. This will also net you the achievement;



From here you have 2 options;

Option 1: Grind daily quests and scouting for encounters.

You can gain reputation points for the following

- Daily: Vital Equipment - Complete the quest and either accept the reward (+200) or donate the reward to Foundation (+250)
- Daily: Retirement Plan - During the Raider quest, tell the former Raider to move to Foundation with a Charisma 8 check (+25)
- Daily: Photo Opportunity - Take the photos to Ward and decline the reward (+75)
- Encounter: Faction Vs Creature - Keep the Settlers alive (+10)
- Encounter: Faction Vs Faction - Do not fire upon the Settlers and keep them alive (+25)
- Encounter: Send people to the Foundation - Use charisma checks to send people to the Foundation


As you can see the majority of your remaining points will likely come from the "Vital Equipment" daily quest. Which may take upwards of around 32+ days if you were to complete this quest only, once per day. The daily quest takes roughly 5 mins so it wouldn't be too bad to just hop on each day to do this.


Option 2: Glitch for Daily: Vital Equipment

It is possible to perform a glitch to complete "Vital equipment" multiple times in a single session. It takes a little preparation and you must be careful in performing the steps to ensure it works as planned.

Here is a video I found on Youtube explaining how to perform the glitch:


In summary..
1. Find one of the Daily quest items spawned on the map and put the item in stash (I found the "Intrustion Module" over at Willard Corporate Housing as shown in the video.
2. Go to Foundation, get Daily: Vital Equipment from Ward
3. Remove item from stash, put item back in stash
4. Leave and join new world
5. Remove item from stash
6. Talk to Ward, selecting the bottom chat option for extra rep. DO NOT SKIP ANY DIALOGUE AS THIS FAILS THE GLITCH
7. Put item back in stash
Repeat steps 4 - 7"

Here's how I farmed the reputation for the Foundation
In less than 5 hours I was able to get approximately 20% of the Neighborly bar (last bar until Ally)

Preparation:
Make a dozen of each... Bulk Adhesive / Bulk Concrete / Bulk Steel / Bulk Wood
Carry 6 of each type of Chem
Carry plenty of Purified Water (for yourself and for giving away)
Carry plenty of food for yourself

The Grind:
1. Fast Travel into Flatwoods and turn around so you are looking at the lodge.

2. Go to the lodge and approach the Settler working on the 2nd floor (this will be your sugar daddy).
It's a good idea to wait until he is hammering or painting.
Interact with him to interrupt his actions.
Interact again right away to possibly trigger a dialog that will have him asking for help.

3. Run south down the street, turn left up the driveway before the bridge, then cut through the grass on the right side and continue down that road.
After the downed telephone pole, you'll see another Settler working on a house.
Approach the Settler and interact in the same way (this Settler is usually a dud and will just continue talking).

Repeat steps 2 and 3

Notes:
Some requests have 2 options (you can give either Bulk Concrete or Bulk Wood).
Keep track of your inventory and when you give out the last item of something, fast travel back to camp and resupply.

Here is my 100% Achievement plan for Fallout 76. If you need help on an achievement, hopefully it will help. And let me know if you need any help. THIS achievement is at 20:53 in the video.