Come to Seattle, I'll take you:
1. into Mt. Rainier Natl Park, you pick mileage & elevation.
2. over the American Alps, Hwy 20 east from several possible starting points.
3. Olympic Peninsula
4. San Juan Islands tour
5. gravel = Iron Horse Trail or Snoqualmie Valley Trail
6. Bring a passport and Vancouver or Victoria open up
7. Great paved/gravel from Blaine, WA to Pt Roberts USA, all along a Canadian Bay, includes 4 border 'checks'.

Several of these destinations could each become a week long trip, not just ride and move-on.