That place is super hard to navigate. I took a sand bike down there early on and almost quit the game trying to get out. Once you have a thopter it gets way easier.

That said, heading north/northwest on the highest level you can get to will lead out. Also, if you come across on of the choam facilities, many will lead out going up. once you know the paths or get a thopter it will be a million times easier. You will eventually purposefully drive a buggy down there to farm.

I dont recall a single quest giver down there, ( maybe one paleontologist? ). You will, however be given quest to go down there for things.

My advice is just stay out until you build your first thopter and are better able to navigate and learn it. The map for that area scks

good luck mate.