I know of a few CSU alumni who either did or do live in Cheyenne. I even see some people wearing CSU paraphernalia around town. I certainly see more Nebraska Cornhuskers gear around, but I do not know how much of that is bandwagon gear, how much belongs to to alumni, and how much is just folks who live in Nebraska (but never attended UNL) and are shopping in Cheyenne.
I do not know how many make the trip to Ft. Collins for games. In my experience, it is probably a function of the same variables as apply to UW alumni living in Cheyenne. I know that we can get both UW and CSU games on the radio here in Cheyenne.