I like the route Jamawani suggested with one alternative to consider. From Arco, ID go west on Rt 20 past Craters of the Moon National Monument(Park?) then take Rt 75 north through Hailey, Sun Valley to Stanley. The routes rejoin at that point. Jamawani's route appears to suggest going north of Arco on Rt 93 to Challis. Both are nice routes but I like the ride over Galena Pass between Ketchum an Stanley.

Once you get to Banks, ID you could go north to McCall/New Meadows and pick up the TA going west or go southwest toward Ontario, OR and pick up Rt 26. That will hook you up to the TA route in Austin, OR. Both are nice routes. The Rt 26 route has very few services from Vale, OR to Unity, OR - I only remember one small store in Brogan.

I've ridden that route as late as late October into early November. If going that late be prepared for snow and ice and cold. But, that said, there were no tourists, few cars and a lot of helpful people offering me places to stay almost everynight across ID and OR.

The only significant, sustained wind, i.e., all day headwind, that I had on that route was in south central ID. The ride along Rt 26 through OR was quite nice.