Hi
although its canadian, the volume 4 in the anne and laurence Yeardon Jones "Dreamspeaker" series "Dreamspeaker Cruising Guide Series: The San Juan Islands: Volume 4" is very good and we have used it quite a bit. also available from amazon
Amazon.com: A Dreamspeaker Cruising Guide: Vol. 4 - The San Juan Islands, 1st Ed.: Anne Yeadon-Jones, null, Laurence Yeadon-Jones: Books
have fun. the san juans are great.