Best loop in the state: east out of Boulder, UT, on Burr Trail, through the ungodly backside of Capital Reef Nat. Park. When you reach 95, go north to Hanksville, then due west on 24 to Torrey, then due south on 12 to Boulder (extra points for riding 12 from Boulder to Escalante.) It is the most beautiful loop in the continental United States, Europe, Africa, Australia, or South America. I haven't been to Antartica or Asia.