The park at Swains Lake is really nice. There is lake access to fish, playgrounds for the kids, and a nice pavilion. The campground sites are pretty close together. It's a nice place to camp during the week, but it did get really crowded on summer weekends. I will say the shower house is GREAT! Individual showers with locking doors for complete privacy.
The location is great to day trip around the area. We enjoyed a day in Kalamazoo. Jackson isn't far with major grocery stores and shopping.