Slabs, Qurtzite, or other

Well, I think you might find Terlingua to be like the slabs and Q in certain ways. There are miles and miles of desert, with fringe people living in things with wheels. There are no particular free camping areas, but with a little asking around you could come up with something free or dirt cheap. Stop at a couple of the local establishments and ask, you'll find something. You'd have to be a bit adventurous to go down there based on such advice, but if you would consider the slabs, you must be.