Minneapolis to Canada to Niagara, back thru UP Michigan

I agree about the suggestion to wait until spring.

But seriously, while I can't offer any tips on the Northern side of that trip, I can assure you that the UP is fabulous. At least in warm weather. I'd plan on spending several days there and seeing the sights. The rivers, the woods, the waterfalls are all great. Not much in the way of cities and nightlife, but a campers' paradise.