I have some suggestions for the portion between Thunder Bay and the US border. Rather than cruise down highway 61 along with every other tourist and traveler, follow something like this: http://goo.gl/maps/cwpAE
Also, go see Kakabeka Falls west of Thunder Bay.
Be sure to eat at the Madhouse in Thunder Bay. Go in and ask for Feliz and tell him you're from ADVrider.
It might take me a bit of searching through my notes to find the coordinates, but this waterfall is hidden off highway 17 on the north side of Lake Superior, if you're into waterfalls.
Oh, and I almost forgot. Stop at the Pigeon River Provincial Park, right before you cross into the US. They have some short hiking trails, one of them leads back to the High Falls of the Pigeon River. It's very impressive and you'll be the only one there.
Grand Portage National Monument on the US side is pretty neat too, if you like history.