I just completed a trip there.
We stayed at the Dunewood National Park campgrounds in IN dunes (no hook ups). Really nice restaurant next door (Barletts) and close to train station to Chicago. Also great view of skyline across the lake. Mich City is OK place too.
If you want to stay at a nice resort village, I really liked the Michigan Van Buren Campground (electric) in South Haven. South Haven and Saugatuck are destinations unto themselves. It's picturesque. By comparison, Indiana is a little run down with terrible roads. South Haven is too far for Chicago day trips.