Day 1: Leave Canada- stay in the Frankenmuth area- do some shopping.
Day 2: Leave early to Traverse City- Spend the afternoon driving to wineries.
Day 3: Head to Mackinaw Island for the day- rent bikes.
Day 4: Sleeping Bear Dunes NP for the day- hike, picnic, enjoy the scenery.
Day 5: Head back home.
I know its a rushed itinery, but this is all the time I have. Anything else that is a must-do??