South Carolina to UP of Michigan trip this Sept/Oct

We are planning a three week trip from South Carolina to the UP of Michigan at the end of September into October. We plan on going into Canada at Sault Ste. Marie for a couple days then back south over to Green Bay and up to Washington Island before heading back south. Research shows plenty of camp grounds. We hope to catch the color foliage just right and hope to find space at the many camp grounds as we not going to make any reservations in advance.

I welcome any advice on camp grounds, attractions and the crossing into Canada. My wife and I will be traveling in our 30" MH. Thanks!

Patrick