That part of Texas is our favorite. Check out Alpine, Ft. Davis, and the Ft. Davis state park. We have enjoyed Alpine and stayed at the Lost Alaskan RV Park. Great owners and facilities. About the distance to everything--everything will be a good drive to and back regardless of where you stay--and in BBNP the speed limit is 45 mph! But enjoy it all. Also check out Big Bend Ranch State Park on the Texas Parks and Wildlife website--no RV camping but a really interesting place. McDonald Observatory star parties are very good--hope there is no moon. Take note, the road into the Basin in BBNP has restrictions on trailer length--I would just not take a trailer up that road! IT will be HOT in September--probably over 100 most days but can cool down after sunset.