Castle Gap park is near Crane, TX, about an hour south of Midland, TX. Google shows the park. It's situated at a little pass in a mesa topped by windmills. The area around Midland is quite flat, with some slight rolling, but no mesas. The mesa near Castle Gap is the first mesa-like edifice south of Midland. Sabkha and I drove down there, and we found Castle Gap road, and we drove it to a gate that said private property. We couldn't go any farther. As far as I could tell, this is the only access to the "park".
Where does one go to tromp in the desert around Midland? In Arizona and New Mexico, there's always BLM or National Forest land not far away. I don't favor government ownership of land, but it sure affords a lot more recreational opportunities. Is there an alliance of landowners than will let you have access? Maybe a hunting lease is the solution? Or buying a piece of land. The area to the south of the Mesa, around McCamey, TX, seemed pretty cool and had nice views to the south, where it seems the elevation drops off, giving the impression that you're up on a big rise. FM 2463, heading north along the east side of the mesa, also had a nice rural feel. Once north of the mesa again on the way home, the desert quickly gets pretty boring in terms of meso-topography.