If you are going via Del Rio. There is Amistad national recreation area around the lake right off 90. 2-3 campgrounds, one on the lake with lake views. We stayed at San Pedro. Nice CS with sun shelter, NO hookups, No water or dump station, pit pots. I think it was $6 per night and $3 after my DAV discount.
We like the CG, idea for an over night stay. There was maybe 3 campers there.
Art & Joyce
35' DP Endeavor being pushed by a Kia Soul