Get the passports, you may want to come back often once you have visited Canada!
If you want more wilderness than population, you may find more on the Canadian side of the Great Lakes. Northern Michigan not included, follow Lake Huron through Michigan, great area.
Lake Superior, Northern Ontario. The ride from Thunder Bay to the Sioux should be on everyone's bucket list.
Lake Huron, you could do the circle. Cross at Sault St Marie, circle lake Huron back to Sarnia/Port Huron. Excellent views, beautiful rock, , loads of camping, hiking, lakes and beautiful beaches. Loads to do!
You could stay in Canada and head east to Niagra Falls. Sorry but the Canadian side has more to offer than the American side and the views are lots better. Besides the falls the area is bountiful of vineyards and fruit farms, peaches etc. Niagra on the Lake very historical. Lake Erie/Lake ontario is Welland Canal. Niagra is about an hour and half to Toronto.
There are way to many things to mention in Toronto area..CN tower, Air Canada Centre.
You really need to determine your amount of time. Ask us Canadians from each area what there is to offer. It is really a beautiful place to visit.
As you can tell I am a little bias, I love Northern Ontario. It really is a gift to us all