We visited this park in October - there was some rain !! - the owls were wonderful.  Taking the ferry across works easily, there was firewood at the park - There were plenty of sites to choose from in Oct.  (and sort of fun for us - it's a "new" campground in that the current picnic area used to be the campground - kind of like a field with the sites around the edge) Now the campground is lovely with pretty private sites in the woods.  Again the hiking is really nice, and access to the Lake is along a sand beach as well as a boggy boardwalk parallel to the shoreline - Getting ice for our cooler was a little iffy in October as the main options in summer were closed by but a local bar sold us a bag of their ice and all was good.  In addition to the hiking the State Historical Society runs a site on Madeline Island centered around the fur trade of earlier times.  Limited hours.