I figure that the route you describe is roughly 1200 miles. There is so much to see and do on the Washington and Oregon coast, I don't see how you could do it justice in the max 10 days you list.
Although, the drive around the Olympic Peninsular is great, with lots of interesting stops, I would forgo this part of your trip and just head to Astoria and drive south to Crescent City, CA, then head inland to I-5 and back home.
Just doing this leg would take at least a week, maybe more, depending on your interests. There are several lighthouses on the route that I like plus other great places of interest. An interest outing would be to take the Mail boat up the Rouge River.
