Renting snowmobiles isn't going to save you money, that's for sure. But if that's what you want to do, you should go around january or february at Cooke City, Montana. The mountains are huge and the base is usually around 100" up there, not to mention it's a big snowmobile town--it's also been in a couple movies and on a few magazine covers. Make sure to bring all your backcountry gear and check www.mtavalanche.com
for snowpack information before you go (and while you're there, if you can). Right now it isn't looking like anything is going to be all that great around thanksgiving, so plan later in the year if possible.