There's a couple variables with cell service, maybe voice is okay, but not 4G. I have Verizon and I can be at the foot of the tower just south of Antonito and I can't send a text message. I guess its not their tower! But in Chama, I have all the services I use.
I once worked for a large company that tried to sell quality of service test equipment to the cell phone providers world wide. Most of those carriers weren't interested in measuring their quality, they just figured out where to add towers by where their complaints came from. We had a box that could be put in the trunk of a car, like a taxi, and as it drove around it could produce a map to show what the service quality was. Neat idea, but I don't think there's a much of a market for that.
Bill Kepner