West Texas such as Midland/Odessa, etc. is pretty barren. Big Bend National Park is beautiful, but you should plan to go there in the fall or spring as can be very hot. We visited Palo Duro Canyon in the panhandle years ago and enjoyed it. Can't remember much about it, but we rode horses there. South Texas right now is covered up with wildflowers and cactus blooming so very beautiful and weather is great. The TX Hill Country around Kerrville, Fredricksburg, etc. is very beautiful now with bluebonnets. Lots to do around there also. We also are doing as you say and picking one area and really exploring and enjoying it instead of trying to run like crazy to visit a bunch of places in one trip.