Edmonds has a fun downtown with lots of local shops and restaurants and small beach access, with a short paved walkway along the beach. It'll be cold, but the beach is always lovely, right? You can also take the ferry here to Kingston, where there's a small walkable area, again, with shops and restaurants. We'd recommend walking on to the ferry, since there's not a lot to do with your car in Kingston. Mukilteo Beach: This beach is more rugged than Edmonds, though still walkable and a little longer. Instead of shops there's a great playground area for kids and you can have fish and chips at the local favorite, Ivar's. Here you can take the ferry to Whidbey Island (Clinton) where there's a nice long beach but the shops are an uphill climb so either take your car or take this ride just for the views.
Pike Place Market--Though it's a bit further trek to Seattle, the Market never disappoints. Dress warmly; much of the market is outdoors or partially enclosed, though it is all covered so don't worry too much about the rain. There are lots of local crafters and food vendors, along with the first Starbucks, the gum wall downstairs, the iconic fish market and great views of the Sound and the Seattle Great Wheel.