We had such a great stay at the Nunda Shoal Campground. It's situated directly next to the Calamus Reservoir, and there is at least one path that leads right to the sandy beach. It's technically for RVs, but we ended up staying there because the nearby tent campground was completely vacant, and we'd rather stay in a more populated area. There are several coin-operated showers that work pretty well. The camp hosts that were present when we were there were incedibly kind, and we really enjoyed chatting with them.