Before investing much time and money in a prairie dog hunt, you might want to Google "plague and prairie dogs" in the Dakotas. This older article (below) describes the problem. There's more up to date info available online and from USF&W.
Dang, Shep, it's not like anyone is going to eat the PDs they shoot in South Dakota or anywhere else. In fact, PD hunting is one way of limiting the spread of plague. Think about it, you have fun while you are doing a service. I say go ahead and invest!