Every year I camp on the Green Lake side of Interlochen State Park, and this year was the first year I allowed a guest - my fiance. It's an absolutely beautiful state park, with lots of access to the lakes and in close proximity to Traverse City and Leelanau, without the tourist rush. The only thing I wish is that it was a little more quiet, because it is a very popular campground so they're usually booked up, but that's what we get for it being such a nice spot. I book the same spot every year with a great view of the lake, but the grounds aren't lacking for beautiful campsites! The store on the other side of the park is convenient. It's also Michigan's first official state park, which is neat!
I highly recommend taking the time to travel up the Leelanau Peninsula and visiting Fishtown and the Sutton's Bay Farmers Market on Saturdays during the summer. Also highly recommend St Ambrose Cellars in Beaulah if you like mead.