Sept 10th through Sept 17th.
This was our home base for our Seattle trip, the park was located right between Seattle and Tacoma, The park has a nice beach on Puget Sound, which was about a 1/2 mile hike from the campground.
Our site was a pretty tight fit for our 26′ rig, but we made it work, the prices were very reasonable and complete with full water, sewer, and electric hookups. There were some larger pull through sites that can accommodate larger rigs, but they were all booked when we booked our site (we booked in June for our Sept trip)