Idaho starts in Tremonton, UT and ends in Payette, ID. Most of the roads are dirt-based and muddy when wet, so keep that in mind. There is a good mixture of back road pavement, Jeep roads, and forest service roads. The countryside is beautiful and includes lots of potato fields. If you get there during harvest, it is really a sight to see.
On the Western side of American Fall, enter the Craters of the Moon National Monument section, a 60-mile stretch of lava rocks. You could think that you were really on the moon here.
Then, it’s Challis National Forest, Sawtooth National Forest, and into Sun Valley Ski Resort and the town of Ketchum, ID. Rooms are expensive here, so go on to Featherville- you’ll like it. Call for a reservation first (info on map #4/#5). The section north of Featherville, toward Rocky Bar, is a must. Eat lunch in Idaho City and end in Payette. Idaho is fun and beautiful, with a good mixture of terrain.