Break up the trip.
People in New England are used to being able to drive half a day or less and be in another state, but that ain't how it works in Michigan. Unless you're wildly wealthy (let's be friends) and can afford to fly into one of the small airports in northern Michigan, you'll probably be driving from one of the larger, more southern hubs, like Detroit. My brother, Kevin, lives in Petoskey, Michigan, so we drove up to his place one day (roughly 4.5 hours), hung out around town, and then continued on to Munising (where the Pictured Rocks are) the next morning (another 2.5 hours).
Northern Michigan, whether you're on the Upper or Lower Peninsula, is gorgeous, so it's worth spending time in some of the cities along the way. Though we didn't stop there, Mackinaw City is a popular spot, along with Mackinac Island, which is entirely car-free and accessible only by ferry (that's where all the famous fudge comes from). Traverse City is known for its cherries. And Petoskey and Harbor Springs are cute beach towns that are also close to the major Michigan ski resorts, Boyne and Nub's Nob.
If you're near Harbor Springs, I highly recommend checking out Pond Hill Farm, which has a winery, brewery, and cafe, and is a working farm (there were piglets!). We did a tasting in the winery (the Cottage White and 2013 Chardonnay were my favorites, though the cherry wine was pretty interesting, too) and enjoyed the beautiful view of the grounds. They also have farm-to-table dinners and barn dances, which I really, really wished I could go to. Basically, this would be my regular hangout spot if I was a local.
For dinner, we tried Barrel Back, which was right on the water of nearby Walloon Lake. The food was good, the view was great, and there was randomly a bouncy castle set up right outside. Pretty much the perfect combination.