This is one of our favorite spots in the area. I recommend West Beach in the park to avoid the crowds. Parking near the bridge is difficult during peak times. The water is ice-cold so even in the summer it is not swimmable.
Seattle is a little over an hour away from Mount Vernon, but the commute varies considerably depending on traffic. Accommodations in the city are significantly more expensive than in Skagit Valley. Be prepared to pay $20 or more to park near tourist attractions, like Pike Place Market. Popular attractions include Pike Place Market, the Space Needle, the Seattle Underground Tour, and more.
Bellingham is Seattle-light. It has a lot of the appeal of Seattle without the stress of traffic and parking. It has a charming downtown business district, great dining, as well as beautiful parks and trails. We recommend Hokkai Ramen, Mallard Ice Cream, Pure Bliss Desserts, and Muto lzakaya for dining. Neko is an adorable Japanese-themed cat café that serves Japanese snacks while you hang out with adoptable cats. Babygreens is a funky coffee/plant shop in the area, and Boulevard Park is a lovely spot near the marina to grab a cup of coffee and take a walk by the water.
If you're on Whidbey Island, pop over to the lavender farm. Stroll around the beautiful lavender fields and get plenty of vacay photos for the 'gram. If you visit, you must stop at their separate storefront, also located in Coupeville, for lavender tea, essential oils, and fresh scones.
We highly recommend you make your way out to Whidbey Island while you're in town. At a minimum, we suggest you stop by Deception Pass state park. If you choose to make a day of it, we recommend grabbing a meal at Harbor Sushi, Jumbo Burrito, or Whidbey Island Bagel Factory. Don't forget to stop at K&R Farms' farm stand, located right outside of Oak Harbor, for local ice cream served in fresh waffle cones.