Didn't mention Bell Harbor in the first post but agree with all of the folks who reccomended it. We have a 22 foot Seasport and are often the smallest boat-the plus is they always find us a spot. It is a great way to spend some time in Seattle.
There are lots of places in the South Puget sound. Dockton in Quartermaster Harbor is a nice place for the day. If you want to explore Tacoma go to Dock Street Marina-within walking distance of museums, restaurants, etc. Gig Harbor is a must. Olympia has a great farmers market within walking...