Welcome to YT! A small playpen would work. They are high enough so that there should be no way a Yorkie can jump out of there. Put in some toys, some clothes with your 'scent' on it, and let her in there to play when you are doing other stuff. Otherwise, I'd suggest putting a harness on her and keeping her on a leash, especially since she is so younng.
There's quite a few campers and travellers on here, I bet one of them will have some good suggestions for camping.
