Welcome! I'm in Weston County, in the NE corner of the state.
Might be different in Cheyenne or Casper and that area, but around here you'd pretty much have to build apartments first. There are no such thing as "condos" in this area, far as I know. Some folks buy old trailers and fix them up to rent. I know a few people doing fair at that, but spaces to park them are as hard to find as hen's teeth mostly. If you bought land and put in a trailer park, you'd probably do well.
Rentals have always been hard to find here. The economy tends to go through booms and busts, with lots of people moving in when there's more work (many living in RVs), then leaving when the jobs dry up. Happens all the time. Rentals would sit empty at least part of the time in a bust period, which is probably one good reason there are not very many available any time.
Those who live in other areas might be able to give you better info. Come visit and see for yourself too!