Southern Utah is beautiful. The Jem Trail was one of the best times I've ever had on a mountain bike. It's not that long, not that hard and not as well known as some other trails, but it was the flowiest trail I've ridden. (I think Bike magazine voted it Best Flow, which I would agree with). Gooseberry Mesa was loads of fun, too, though it was easy to get lost, or at least get off the trail that we thought we were on. And if you are ever near Bryce Canyon National Park, try out Thunder Mountain. The views/scenery are worth it, alone. The trail is challenging at times, but not too severe. The last couple miles are fast downhill, the kind on which you don't use your brakes much but don't really have to pedal either.