I'll be in Moab, UT for 3 or 4 days next month. I'm interested in some relatively mild mountain biking. My wife and I are in our 50s, in decent shape, but not looking for the crazy thrill rides that I see some of you impressive young mountain bikers handle. We're more into riding for the scenery and ambiance of the trails. We would have to rent mountain bikes while we're there. Any suggestions?