Why bother with a campground when there is 50 miles of prime camping on public lands between Chama and Antonito? Much of it a short morning drive to one end of the line or other. Or up the Rio Chama.
I've camped at Big Horn, crossing near MP 302.5, near Osier, Cumbres Pass, Trujillo Meadows, and along 445 up the Rio Chama.
I realize aged bodies might want the comfort and ease of improved restrooms and showers. There are compact folding latrine chairs for camping, as well as 5 gallon bucket conversion systems. A washcloth or luffa and water warmed over a camp stove is a pretty reliable shower replacement. The wild animals aren't going to judge a full moon day or night!
The best part about camping near the ROW is being able to stare up at the endless night sky, with that deep gentle chill of the San Juans as you look far into the same Milky Way Galaxy the grading crews looked up at in 1881.