Location: Denver to Cheyenne, everywhere in between
Unfortunately, you're pretty much out of luck. The closest OHV area is Veedavoo, and I'm sure you saw that on your way to the snowies. I looked all over and everything there is private owned land and you can't wheel on it unless you know the owner. And like you said, the only time you find mud is right after it rains, or when the snow starts to melt, and even then, all the trails on public land are closed to "protect the environment". I think that's one of the main reasons that Wyoming is the least densely populated state in the country. Heck, it's why I moved. Sorry I couldn't tell you otherwise!