Don't overlook this very large, lesser traveled state park, I enjoy it more than Big Bend NP. I cover this 300,000+ acre park in my book "TEXAS BADLANDS: The Ultimate Black and White Journey" (available on Amazon) extensively in Chapter 4 "The Other Side of Nowhere."
Be sure to purchase a Big Bend Ranch SP Topo Map at the Visitors Centers for precise location/navigation. The drive from Presidio, Texas to Lajitas, Texas on TX FM 170 is one of the most underrated drives in the United States.