FWIW, I talked to the Rio Grande Gorge visitors center. There are the two BLM parks on the river, Rio Bravo and Pilar Campgounds that have E&W. They only have about a dozen sites, between the two, with 50A and water, and big rig access, but no WW dumps. They are on a 1st come basis. No reservations. They are about 15 mi south of Taos and $15/night, $7.50 w senior pass.