poorly. This part of WY is not so good for surface water, and isn't a great agricultural region. Lots of windmills would be put up to pump water. Due to the large number (comparatively) of people in Cheyenne vs. the agricultural ability of the area to grow food... mass starvation. Eventually, after the Great Die-Off, you'd have a small number of people surviving mainly on herding cattle and growing grain and vegetables in the places suitable for it... but the growing season here is damn short, so people would be limited to growing those things that grow fast and produce a lot in a short time... potatoes, barley, etc. Without rail and truck traffic, the area around here really isn't that important or strategic, so it's unlikely that any of the warlord wannabees will bother whoever is left...