how far do you want to drive?
Silver Lake will be packed, but if you have never been it's an awesome site,
Sleeping Bear Dunes if you want to avoid the vehicles, going up the west coast I like better then the East coast,
Torch Lake was put in some travel book/mag as the most beautiful lake in the world or something like that,
Traverse City is nice
Mackinac Island is pretty cool if you've never been, and no car on the Island, so lots of hiking or biking
Lots of great places in the UP, like waterfalls,