Great suggestions from Budget Queen, especially the Whidbey Island loop. (if you take that drive be sure to stop at Fort Casey, interesting old military sight).
Yes, you would need a car for any of those trips.
Another nice day trip would be to Port Townsend on the Olympic Peninsula; lovely old Victorian homes.


DASEY, here's the link to the ferry system. The summer schedule isn't up yet.
http://www.wsdot.wa.gov/ferries/info_desk/route-maps/