If there is one spot i'd recommend, out of all of the camping on the ferry-served san juan islands, it's Moran State Park, on Oracas Island. We stayed in the Mountain Lake section of the State Park, and it was amazing. Secluded. Quiet. Beautiful. This would be a tough spot to camp during a busy weekend however as the spots are super close, but it's worth it. We camped mid week in May and had the campground to ourselves. It was heavenly. The lake is placid and clear, there were NO mosquitos at all. FYI: Cell coverage is spotty, verizon's coverage was nonexistent, but the ranger had at&t and said she had some coverage. There is a pay phone just up the road in case of emergencies. The Cascades Lakes campground looks more suited to resort camping with showers, a lake with boat rentals, and a small store, but i much prefer the Mountain Lake section. Bring a paddle board, or a canoe, or your hiking shoes, and leave reality behind for a few days or weeks. : ) The hike that goes around mountain lake is spectacular. Moss, old growth trees, creeks to cross, wildflowers, and best of all, if the campground is empty, you'll have the hiking trail to yourself as well!