When were in a 4x4 club years ago, we used to go riding up around the lakes area of Sam Rayburn. Unfortunately, I think the BLM shut down these trails.
Now days, since we have been into the ATV riding scene, we load up and go to Shiloh Ridge in Alto, Texas. Or also General Sams Off0road park in Huntsville, TX. Both are pretty good parks in my opinion. They offer a good variety of terrain for all types of vehicles.
Just don't go on a big event weekend if you don't like crowds, or idiots.