Been all over Utah several times. The ONLY road you need to be aware of is Rt.261 between Mexican Hat & Natural Bridges. There is one small area that may not be shown on some maps. Its called the Moki Dugway Switchbacks. The nice hyway suddenly turns into a, narrow in spots, dirt road for about 2 miles while it climbs up a very steep mesa wall. Don't worry about Rt.12. Its a beautiful drive. The Hogsback section has plenty of room. The only road in the USA that gives me the 'willeys' is the Million dollar hyway Rt.550 in Colorado & a short section of the park road atop Crater lake.