That’s what I’ve been thinking. If CellularOne operated a PCS network, all Sprint would have to do is swap CellularOne’s old RRUs out with Samsung NV RRUs and ground equipment. They could run 1x/LTE over CellOne’s antennae ala Sprint’s current (and ongoing) GMO deployment.
With the ~200 to 250 sites I estimate they have, the whole footprint could probably be up and running in under three months (~3 sites a day).
Sadly, though, as far as I know, there aren’t plans for an extensive buildout in Montana in the immediate future. I’d keep my eyes on South Dakota and Wyoming if I were you .