Rainbow Moon

All is post game content

Below is a very effective way to both reach level 500 and earn 500,000 coins in your inventory. I highly recommend waiting until you've completed the side mission needed to exceed the level 250 cap. In the Broad Kennel (the dungeon below the town of Felad, in the southwest portion of Arillia), all the way to the left after walking in, there will be two level 190 rock monsters off in a little area by themselves (the dematerializer is needed for access). Each has over 35 monsters in their fights, all level 190 rock monsters. They spawn every 3 days in the dungeon, so each day after you've completed both fights, keep alternating use of the nearby camp fire outside and lodge in Felad to progress the days. Selling spoils from these battles (Living Rock and Lifeless Stone) can help towards the "Half a Millionare" trophy since you will begin to accumulate a lot them after everytime this is repeated.

These fights are managable with at least 3 party members at or around at least level 250, but I'd highly recommend crafting items into their equipment that gives the wearer permanent buffs. The best for this are:

Essence of the Moon (drop info: http://rainbowmoon.wikispaces.com/Essence+of+the+Moon) - Adds permanent "Inflate" status to equipment

Toxic Ixiolit (drop info: http://rainbowmoon.wikispaces.com/Toxic+Ixiolit) - Adds permanent "Haste" status to equipment

Also by completing the Jade Statue III sidequest, your lottery wheel level will be upgraded, allowing wagers of $35,000. The S, A, B, & C level equipment gained from this are mostly Ultimate level equipment that innately boosts the respective characters stats significantly AND has many of these useful buffs already included in them.

Lastly, I recommend using party members who have ranged attacks that can do major damage to large groups of enemies per turn (Balden, Trisha, and Serena are good for this), has passive skill Coin Collector learned & equipped, and ALL having passive skill XP Rain learned & equipped. The latter 2 mentioned passive skills helps gets the most out of the battles for the trophies.

Credit to MrKratosmd for the video

Once you've got the "Level God" trophy make sure to save your game and then sell everything you've got including equipped weapons and armour. Given you should be using ultimate equipment + crafting at this point, you should make enough to get the trophy and also to buy any remaining scrolls you need for "Skilled!". Once the trophies pop you can reload to get your stuff back.