We took our camper up to the Duluth area in July of 2007.  We had never been to Fond du Lac campground, but we decided to give it a try.  They don't take reservations, but the weekend that we went there it wasn't a problem.  This campground is no frills, but it has all of the basics covered - if you have camped at federal campground, then Fond du Lac will seem familiar.  It even has a "camp host" and a drop box for payment.  Unlike a federal campground however, this campground has sites with electric and water hookups and showers.