Turn Island is an awesome little state park tucked right next to San Juan Island. The access is only via boat and is a nice little get away spot. It has the feel of a hike/bike camp ground with a handful of spots along the west side of the island. The camping is CO-OPed by the fish and wildlife service and the WA state Parks and Rec commission.
We stayed for two nights and had a very lovely time with a short hike around the island and all the beach you could explore. We also took our Kayaks around and saw many different sea life along the way.