I went to school up in Bellingham, Washington. Lucky for me I still have family and friends who live there so I visit "The City of Subdued Excitement" often. I try to allow myself enough time to do one of my favorite drives in Washington along the way. Spring and summer are the best time for this adventure. From Seattle, head north on I-5, take exit 230, get on WA 20 towards Anacortes for a few minutes then take a right onto Farm to Market Road. Roll the windows down (even if you have to crank the heat), drive slow and stop along the way. In the spring the fields are full of daffodils and tulips. In summer the sunflowers tower over you.
The Farm to Market Road will bring you right into Edison. If it's before noon stop at Tweets for the best frittata of your life (be prepared to wait). If you're passing through in the afternoon or evening hit up Mariposa or the Edison Inn. Walk the street and pop into whatever shop or gallery might be open. If that's all you have time for make sure you hit up Bayview State Park (or rent a cabin and stay there for a night) before heading back.
The second half of one of Washington's best road trips is Chuckanut Drive. From Edison take a right on Bow Hill Road and then a left on Chuckanut. Stop at every overlook or oyster bar that your heart desires.
Make sure you visit Larabee State park and walk down to the water. If you have time, hike up to Fragrance Lake and don't skip the overlook. And if you want a hardcore work out hike up to Oyster Dome. From there continue to Bellingham or head back to Seattle.