so how should one go about earning 500k gold?

[TheCakeIsNotAPie]

with only a couple levels left to go to 52, i don't have nearly enough money even with selling my mats to proceed to the hero class

[Sargent Q]

Put your Assist XP into Gold for your last 2 levels.  It should get you much close.  It will take a while to get those lat 2 levels though.

[greekdragonkdl]

Play as much ragnarok mode as possible. It yields the most xp and mats out of any of the game modes in this mod. It also helps to join a good house that does weekly events as events are usually more organized and much more likely to successfully complete rag runs than public servers are.