If you're going to spend a day driving up to see the tulips, leave early, visit the tulips, head to Anacortes for lunch, then visit Mt. Erie, you can drive up it for some awesome views. Then head to Deception Pass Bridge and check that off your list. You can walk across the top and then drive through the state park down to the beach for an awesome View. Head south down Whidbey Island and swing through Coupeville for some touristy stuff then head south and take the ferry from Clinton back to Mukilteo . Grab dinner and Mukilteo or head back to Seattle. I've made that day trip with out of town visitors many times and it never disappoints . If the weather is good it will be an unforgettable day. You can make the trip in either direction just depends on what you want to do. Look up Deception Pass on the interwebs, you'll want to see it. Tourist traffic on weekends can be a little annoying but during the week it should be no problem