How do I get through the camp to the cave in Chapter 2 without being seen? One door leads to a bunch of guards, one door I need a key for, and another I can't get past without being noticed by the two men taking of the one puking.

I assume this is Iorveth's side you're talking about and you are talking about sneaking through Henselt's camp? If it is, you're trying to get out the sw gate.

Stuck on this part myself, three doors out of the camp but one can't be interacted with, one has a large group of guards behind it and the other has two guards in front of it. Judging by the layout I assume the one with the guards behind it is the one I'm supposed to leave by (farthest from entry point, leads down to cave entrance). As soon as I go through it the group of guards alerts and even if I start fighting them I get a cutscene showing Geralt pincushioned by arrows.

I don't know how, but you apparently need to do things in a specific order for the events to play out like they're supposed to.

Basically, do exactly what the game guide says. Knock that guy out and wait for the guards to come out. You possibly need to load an earlier save for that to work.

Witcher 2 really doesn't spoon-fed.