Port Townsend is located on the Northeast tip of the Olympic Peninsula, 1 1/2 hours from Seattle including the delightful ferry ride.

Driving directions via the Seattle/Bainbridge ferry:
From Bainbridge follow Highway 3 to the Hood Canal Bridge. Cross the bridge, following Highway 104 to Highway 19, which is the Port Townsend exit.
 

Via the Edmonds/Kingston ferry: At Kingston follow Highway 104 to the Hood Canal Bridge, cross the bridge, and take the Highway 19 exit to Port Townsend.

Once you are in Port Townsend, follow the main road to and through the downtown area to Monroe Street. Turn left onto Monroe, following it to the stop sign at Roosevelt. Turn right and follow Roosevelt for 1/2 block, where the road turns left and becomes Jackson St. Follow Jackson and it will turn right and become Walnut Street. We are on the corner of Walnut and V Streets.

You can also look at http://www.mapquest.com which offer great maps.