My sister was just at Big Bend NP last weekend and loved it. She went with a few of her high school friends. They flew into Midland (MAF), drove down through Fort Stockton for a, "final meal," then stayed at the lodge in the park. They did a halfday kayaking trip on the Rio Grande, and a bit of hiking, and just driving around.
I've been wanting to do a trip to Big Bend, and a side trip to Balmorhea State Park for years....hearing about her trip is making me think. I might whip something together.