How about these MI places (Score 1)

Mackinaw Bridge...if I remember correctly there is a time of year (Labor Day?) that they have a scheduled walk across the bridge and there are plenty of nice places to camp near the bridge. Henry Ford Museum and the related properties, great geeky stuff including Edison's labratory. Also, make sure to hit the Dearborn area and see some of the Ford family houses and his own electric plant he had. How about hitting the US big three, Ford, GM and Chrysler (no particular order) and going on some visitor trips through their buildings if possible. Finally, how about the Detroit Institue of Arts (DIA) It's still a pretty nice place to go.