The WWTA is a small non-profit membership organization dedicated to the recreational use and environmental stewardship of Washington State waterways. They have a network of water trails and campsites for use by human powered craft. The jewel of the trails is the Cascadia Marine Trail, A salt water trail that stretches over 140 miles, from the Canadian border on the north to southernmost Puget Sound near Olympia. The CMT includes 58 campsites which are open to people arriving in non-motorized beachable watercraft, as well over 100 legal access points.
Washington Water Trails Association
http://www.wwta.org/home/water-trails/