There is so much to do in Seattle, I drive there every day and still discover something new all the time. The tourist stuff is well published and the places to eat, parks, things to do are all around you. It might be nice to plan a couple of day trips out of town, but spend at least one day in town going to some of the fun stuff. Seattle center, space needle, fountain, etc. then go downtown on the monorail, walk to the pike street market, and Seattle Art Museum.
Tons of water stuff to do, great zoo, great aquarium, professional sports. Very safe city with very little to avoid.