Trip from KS to Big Bend N.P., to Organ Pipe Cactus N.P.

On your way out of Big Bend, stop at McDonald Observatory (one of the world's largest telescopes). Davis Mountains State Park is a nearby campground. Go north up Hwy 54 to Guadalupe Mountains National Park; hike to the top of Gaudalupe Peak if you are up to that sort of thing.

Back on I-10 in New Mexico, stop in Mesilla (just south of Las Cruces) to eat at La Posta, a terific Mexican restaurant. At Tuscon, AZ, visit the Sonora Desert Museum. On the way down to Organ Pipe NP, visit Kitt Peak Observatory.