I would think about doing something along these lines post retirement when I could spent a few months on the road.
To the OP: your proposed trip takes you through SE MN and SW WI. There are some very fine bike paths in that area as well as just fine riding. Check out the Root River trail in SE MN. I'd also check out some of the paths and rides on the MS river. That's beautiful country.
In western SD there is the George Mickelson trail in the Black Hills. I haven't been but it's on my list of places to explore. If you head south into NE you can follow some of the smaller roads in northern NE and check ot the cowboy trail. That will take you through the sandhill region of NE.