Don't forget Big Bend. Boquillos Canyon is a very nice, easy hike. So is Hot Springs. Bring a change of clothes. We like to camp near Terlingua. Allow about 4 days to get a real good feel for the park. If you're coming in from the north west try Davis Mountains SP. Univ Tex has a major telescope there and Fort Davis is real good for history. If you go through San Antonio Rudy's BBQ is a must. "Worst BBQ in Texas". It's been featured on either food or travel channel. Can't go wrong with the coast from Corpus to Galveston.