Great for fall camping, not great for swimming
We camped here in early fall and the full shade sites in mature forest were great. There are a lot of raccoons and the sites even come equipped with a pole for hanging your garbage out of reach of the coons.
The lake, when we went in late August/Early September had a lot of algae on it and wasn't really good to swim, but they do have boat rentals and fishing. It is generally a beautiful lake.
There is a good amount of hiking in the area and it is in close proximity to the Wisconsin Dells, so there is plenty to do.