I never went to Barnwell. I wanted too, but it was up by the Metroplex and never got around to it. There were a few others in the Hill Country that were only open 6-8 times a year. One time I went to a place called Long Ranch. You might try to find that. It's on a river somewhere around Lake Buchanan. There are two others I can't recall the names of right now. Geez, what 3 years will do to my memory.
EDIT: SWR Offroad was one of them, Katemcy Rocks of course (but I like Wolf Caves better)