"Cowboy country"? South Dakota? [:'(]
I'll bet dollars to doughnuts he's from Wyoming. (Me too!)
There are private heards you can hunt around the area. Don't think you even need a license. Prices vary. Locally there is the Terry Bison Ranch.
(307)634-4171. Or
www.terrybisonranch.com
There's a guy in western Nebraska (near Bushnell)that lets you shoot bison. Last time I heard anyway. Art Hottell, (308)673-5565.
So look into private hunts, unless you are dead set on a free ranging hunt.