Tour the northern section of the Olympic Peninsula, visit one of the coastal islands, and roam through a bit of the Cascade Range. On the first day, head from Seattle to Port Townsend, a seaside town with Victorian buildings. Explore shops and galleries, have lunch, and then take the ferry to Whidbey Island, passing through Deception Pass State Park en route to Anacortes. Take a late-afternoon ferry to the San Juan Islands, disembarking on hilly Orcas Island, the more touristy San Juan Island, or quiet Lopez Island. Whichever island you choose, you'll need two full days. On the fourth day, catch an early ferry back to the mainland and head—via Everett and U.S. 2—out on a loop through the North Cascades. Have lunch in Bavarian-style Leavenworth, before crossing Snoqualmie summit via U.S. 97 and I-90. Pass through Cle Elum, and consider stopping in the small, picturesque town of Roslyn for dinner. From here it's less than two hours back to Seattle.
Spend two days exploring the Seattle area, including an afternoon ferry trip to Bainbridge Island. On Day 3, drive southeast to Mt. Rainier National Park and spend the night. On Day 4 drive to Yakima, then make a long southeastern loop through Pasco and Walla Walla on your way to Spokane. Spend the night, then use Day 5 to look around the city. On Day 6, start out early for Moses Lake; then travel northwest along U.S. 2 to explore the apple fields of Wenatchee and Leavenworth. Spend the night, then make a side trip north to Lake Chelan before returning to Seattle.