Desert hawk pretty much nailed the Minnesota end of things. With Superior National Forest along the north shore, there are boondocking opportunities there.
I've only been as far as Thunder Bay in Canada, so perhaps some Canadians can speak to other opportunities there.
In Wisconsin, you will go through Superior (just across from Duluth and it is another port city). Then take US 2 to hwy 13, which takes you along the lake. Chequamegon NF is up that way, so you can boondock there. Apostle Island National Lakeshore is neat, as is a ferry trip to Madeline Island. Bayfield is a quaint little town on the Lake with some touristy attractions.
Red Lake and Bad River Indian Reservations are along the way in WIsconsin if you want some Indian culture or Casinos are your thing. In the UP of Michigan, the Keewenaw Peninsula is very beautiful. Ottawa National Forest (in Western UP) and Hiawatha NF (in central and eastern UP) have campgrounds and also boondocking opportunities. PicturedRocks National Park and Tahquamenon Falls state parks are good visits. Take the boat ride at Pictured Rocks..the only way to truly see the cliffs. Farther to the east, visit Mackinack Island and the Soo Locks. Again , the eastrn unit of Hiawatha NF is there, so boondocking opportunities in that area. Then you're back up to Canada, where I don't know much. Enjoy.
