From Van Horn to Brackettville, US 90 is . . . . . long.
There are scattered services along the way, but most people have to rough camp.
One option that doesn't add significant mileage is to detour via Fort Davis and the Davis Mtns.
Left onto FM 505 7 miles east of Valentine, then Hwy 166 to Hwy 17 to Fort Davis & nearby state park.
Take Hwy 118 south to reconnect to the ST at Alpine. (My RWGPS maps are E-to-W)
https://ridewithgps.com/routes/35663364Another national park option with not quite as many miles is Guadalupe Mountains N.P.
A benefit of this option is you skip riding on Interstate 10. (I hate Interstate riding)
From El Paso head east on US 62/180 - traffic thins out quickly and it gets REALLY empty.
Cornudas Cafe is the ONLY service between eastern El Paso and the park.
(The park website mentions the Salt Flat Cafe - it is long closed.)
The park has camping and water (verify in winter) but only a little gift shop.
https://ridewithgps.com/routes/35672264https://ridewithgps.com/routes/35663575You have to backtrack a few miles to get onto Hwy 54 south to Van Horn.
It really is a beautiful, empty road with distant mountain views. Zero services.
Van Horn is a tourist trap, however.
https://ridewithgps.com/routes/35663432Clearly, the Guadalupe Mountains option is for folks comfortable and experienced with remote riding.
PS - There's very little public land in Texas.
So it is best to ask to remote camp if you can - like at Cornudas.
"Rest Areas" on US 90 are, at most, a pull-out and maybe a picnic table.
Still they are options for camping in a pinch - usually Texas Rangers understand.
PPS - Did I mention how long and empty US 90 was??
Pic - Scenic US 90