The Great River Road on the Borders of Minnesota and Wisconsin.
This is a beautiful road for so many reasons. One feature is you can run down one side in Wisconsin and ride back on the Minnesota side. Both ways give you lots of twisty that skirt the bluffs and river bends. There are plenty of sweet places to pull over and watch the thousands of migrating birds that take the Mississippi Flyway from the Arctic to the Gulf. The BMW crowd rated it one of their top five favorites for the northern mid-west. See you out there!