As a Michigander, I can't say anything about the double-lettered highways in WI, but in August 2011, after rounding the north shore of Lake Superior, I rode south out of Superior WI on US53 to Highway 25, then down Highway 35 along the east bank of the Mississippi River to LaCrosse, and then picked up Highway 33 heading east towards Reedsburg and the Dells. Like 35 coming down the river, Highway 33 is just drop-dead beautiful - rolling country, twist and turns, hilly in the Ontario - Wildcat Mt. State Park area - lightly traveled, small towns, what I'd call "heartland".