I'm planning a tour that will include crossing Idaho east to west. Is the route below viable? I would like to ride through Craters of the Moon National Monument, but nobody seems to go this way. Maybe it's because there are very few services.
There's a short stretch on US 21 southeast of Boise that looks pretty horrendous. US 20 doesn't look like a lot of fun either, but it's probably manageable. There are long stretches on dirt roads that are not on Google Street View, so I have no idea what they are like.
Arco, ID to Vale, OR (Ride With GPS)
by AggroPedestrian