Being from the west side of Michigan I'm quite partial to the Lake Michigan shoreline. The west coast of Michigan has dunes (ck Silver Lake sand dunes north of Muskegon a ways & Sleeping Bear). Wisconsin and Michigan's Lake Huron shoreline do not have them due to the prevailing winds.
If you don't want to camp in Sault Ste Marie check out Brimley State Park about 15 miles west of the Soo. Very grassy with a nice beach.
There's a nice county campground in the lower peninsula south of Petoskey and the north end of Torch Lake in Eastport. Antrim County's Barns Park Campground. Electric only, but nice place and beach.
Indigo Bluff's RV Park west of Traverse City not far from Empire and Sleeping Bear Dunes is a nice private park. They have some FHU sites, but not many. It's a good place to visit the area from. Nice beach in Empire too. Check out Glen Arbor on Glen Lake and further north of that is Leland. Many wineries in this area, the Leelanau Peninsula. This area is my favorite part of the lower peninsula.
South of Empire just east of Frankfort is a fairly new FHU campground called Frankfort Crystal Lake RV Resort. A little plain now, but they've got paved sites. Again, another park from where you can visit the surrounding area.
Also, there is a very nice RV park at the Little River Casino just north of Manistee. It right where M-22 & US-131 meet north of Manistee. The rates are very reasonable for FHUs or Water & electric sites.
