WarChief146, welcome to TFL!
Don't know where exactly you live on the West slope, but if you got a license agent nearby where you can pick up a small game license look for the handbook as well. It will give you the regulations on prairie dogs. Gunnison/White Tail prairie dogs both have a season on them and can be shot on public lands. Black Tail prairie dogs are protected at the present time and can not be shot on public lands so you will have to seek private property to shoot on.
Place a news paper add in the local paper offering up some free labor for shooting privileges. Go down to the local café on the weekend and BS a little bit with the locals and you might get some suggestions on whom to talk to. Just don’t get too pushy and be polite when you get turned down but be persistent and you will find some people who will give you permission.