Although some may consider it a tourist trap, Mackinaw City offers more than just strip malls and souvenir shops. Despite overdevelopment, the town has several things to recommend it—namely, a maritime museum, a lighthouse, two excellent historic parks, several fudge shops, numerous hotel rooms, terrific views of the Great Lakes, and, of course, ferry service to Mackinac Island [1].
Pellston Regional Airport (PLN) (231/539-8441, www.pellstonairport.com [2]) offers commuter service from Detroit [3] via Northwest Airlink. From there, you can rent a vehicle, take U.S. 31 to I-75, and head north to Mackinaw City. Of course, many visitors come to Michigan by car, usually heading for Mackinaw City via I-75 or U.S. 23. Once in town, you can park your vehicle and walk to the shops and eateries.
Links:
[1] http://www.moon.com/destinations/michigan/northeast-michigan/mackinac-island
[2] http://www.pellstonairport.com
[3] http://www.moon.com/destinations/michigan/detroit