You have a number of options if traveling to or from Port Townsend. You can follow US-101 around the western Olympic Peninsula, or take a ferry via Whidbey Island and explore it and the even prettier San Juan Islands to the north. Last, but not least, you can take a middle route across the Kitsap Peninsula, then catch a ferry to Seattle.
This last route, which includes a trip on the very frequent (and frequently crowded) Washington State Ferry ($13; 206/464-6400) between Kingston and Edmonds, has the great advantage of taking you through the lovely old logging town of Port Gamble, a slice of New England on the shores of Puget Sound. The entire town is a historic district, with dozens of immaculate Victorian buildings standing along maple tree–lined streets. After wandering past the saltbox houses, have a look inside the large General Store, which includes a barber shop, a seashell museum, and a small café; or visit the photo-filled historical museum ($2.50; 360/297-8074) across the street.