I go to the Telluride Bluegrass Festival every year in June and we usually take a day to drive thru one of the passes (unfortunately in a 4x4 Suburban, not a RZR). We've done Ophir, Imogene, and some others and its absolutely spectacular. There's also lots of abandoned silver mines in the area which are fun to explore. Its truly amazing country. The one we haven't done is Black Bear. Supposed to be one of the most difficult 4x4 trails in the country, and drops down into Telluride via a couple of beautiful waterfalls and the country's first electric powerplant situated on a cliff right next to a waterfall. There pictures and details on the web you could check out. apparently its only open a month or two per year - the rest of the year its snowed in - June's too early, but August/Sept timeframe might be OK. Black Bear would be perfect for a RZR, but the only thing is that its one-way from the "million dollar highway" over to Telluride, so you'd have to have someone pick you up in Telluride with a trailer.