let's go out to Big Bend National Park.............but that's about a three days' drive from anywhere (except El Paso) in Texas.

For as large as Texas is, it is barely more than hilly. So from that perspective, there are very few good "hiking/backpacking" opportunities, particularly when you consider the lack of public land access. If you know property owners with large tracts of land (Uh, I mean people who own several sections of land), you can get on their land.