New Canyon Campground, Estancia, NM
This is a small, developed campground offered free by Cibola National Forest. It's strictly for tent campers, though it has a small dirt parking area, but only large enough for a few small vehicles. Motorhomes and trailers just won't fit here, unless you're talking tear-drop trailers. Vans, pickup truck campers, or roof-top tents are doable.
Tajique Campground, Estancia, NM
This is a developed campground offered for free by Cibola National Forest. It's a small unit with six sites intended for cars, trucks, and vans. Small RVs can get in, along with teardrop trailers. Anything larger won't be able to get in. It's intended for tent camping, but sleeping in your vehicle is course, fine.