Prob too late but a drive across the North Cascades Highway, State Route 20, up over Washington and Rainy Passes, etc. is considered by many to be the best drive in the state. Stop at the overlook at Washington Pass if you do. Plenty of good day hikes all over that area.
Yeah, taking a ferry to the San Juans would be a good idea too...
Somebody might hae mentioned it. But Cape Flattery is cool. Also. The salmon run is running hot right now. The mouth of the Columbia River opens 1 Aug. PM if you have some questions. I live here.