Advice on Route from Michigan's Upper Penn into Wisconsin

Route wise, US-2 can't be beat. Do you specifically want to visit Wisconsin? You'll cut through a little bit of it and then into Minnesota, driving through beautiful Duluth on the shore of Lake Superior.

With a big rig, look into the parks outside Glacier, the in park rv campground is great but dated, built when RVs were much smaller.

I'm not much help with camping along the way, Both times I made the drive I stayed in Walmarts till Glacier.