From Benson to El Paso is a decent drive. We usually stay at the Flying J at exit O, Anthony, TX, but there are other options nearby. A mile south is the TX Welcome Center with good parking. Across the interstate is Camping World.
Down the road, we like staying at the Walmart in Ft. Stockton.
Or, we like Balmorhea State Park. If you get there before sundown, you can watch the flight of the bats as they come out of the tiles on the campground shelters. Kinda cool :)
Another place we like is the rest stop that is 8 miles west of Sonora. A nice shady stop, pull in and park along the back half circle.
If you're ready to stop at Fredericksburg, there are several rv parks.
Another nice rv park is south of Johnson City just where 290 turns to the west toward Austin.