Craig: To add to what Scott and Greg have said about access along the ROW. The owners of the "Rancho del Oso Pardo" (the former Lobo Lodge) have posted MANY "No trespassing" signs along the ROW this Spring! They run from near Lake Lobato eastward to the second crossing. You could get spoken to if you cross their property.
The RR ROW, from just east of Cresco all the way to Chama, is only 50' on either side of the centerline of the track. I would advise you to check in with the folks at the depot if you intend to walk any significant stretch along the ROW.
Have a great time in God's Country!
Rich