West of Seattle day trip?

Hi
I'm looking for suggestions for a day trip west of Seattle. We are there for 4 days at the end of July and would like to spend one on the "coast" or islands or whatever looks good west of the city. Looking for things like a nice walk on the beach, funky little shops, jaw dropping scenery, etc. all within a 3 hour drive of Dash Point park. We are a family of 4 with two young teens.
Thanks much for the suggestions.