I have been living in Bridgeport, Tx for 2.5 years and as far as i can find, all of the "back country" strips are private. I have flown quite a bit in the hill country and out west (big bend), Del Rio. Lots of ranch strips, all marked private. I have, on some occasions, contacted the owner in advance for permission, usually get a no answer. Can't blame them, no one wants to get sued.
Chris