There is a really cheap way to go to Seattle by public transport. It takes a little bit longer than the direct bus, but it's also convenient and much cheaper. For further information, check out the website
You can drive along the Olympic Peninsula from Olympia, you can come by ferry from Seattle or Victoria, B.C., or the best way, come on your own boat.
Coho Ferry between Port Angeles and Victoria. Check their website for details.
Washington State Ferries Check the website for schedules and reservations.