I like staying at Rio Grande Village campground. They have a concession/convenience store there. The "A" campground area has concrete block restrooms. "B" has porta potties. They also have an RV hookup area next to the store. Stay in "A" if you are tent camping.
The concession store has coin operated showers - bring a roll of quarters. The nature trail there is great. Campground is a short drive to several scenic attractions.
There is an especially dark observing spot at the asphalt parking lot of the Rio Grande Village park headquarters. It will be deserted at night. Only a few miles from camp.
Other folks might recommend the Basin campground - harder to get in there, but its pretty up in the mountains. No store there, but they do have a lodge - not usually easy to reserve a room there at the last minute - but you might get lucky. <edit> Lodge is currently closed due to a recent fire in the area.
Big Bend is a four or five trip (4 days each) area, before you even consider taking any off paved road excursions. Don't do it on your first trip! You can't expect to even scratch the surface on your first trip. Just be comfortable and soak it in.
Get a full tank of gas in Marathon before you drive into the park. Its about 100 miles from Marathon to Rio Grande Village (56 miles from park entrance to Rio Grande Village).
You can get some gas before you drive out at the main park headquarters (about 40 miles from Rio Grande Village). Do not run out of gas. Don't think AAA will save you in the park. That is the only spot you can get fuel in the entire park. You have been warned!
Good luck. Big Bend is one of my favorite camping areas in USA.
Edited by siriusandthepup, 03 May 2021 - 07:48 AM.