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While four days is more than many people would devote to a drive from Seattle to San Francisco, it may not be enough to do everything that you would like. Choices must be made, unfortunately, and there are a couple of places that I would highly recommend to you that aren't on your list as yet. The first general recommendation would be to get a few more miles farther down the road on your first day. Many of your "must see" location are in the southern portion of your trip and you should get there with some speed when you are freshly starting out.
Specifically, at Olympia I'd take US-101
north towards Port Angeles and then OR-8/US-12/OR-107 west to US-101
south. (You can see what's happening on a map.) Follow US-101 down the coast, perhaps using WA-401 as a shortcut between Nemah and Astoria. Just south of Astoria is one of the sites that I'd suggest you visit if you possibly can:
Fort Clatsop. There are more than a dozen state parks along the Oregon coast, most of which offer trails along bluffs overlooking the ocean, views of sea stacks, access to the shore, or all of the above. Consult your map and pick a few that fit in with your other stops or long driving sections. But ultimately you should try to get a bit farther south than Cannon Beach which, after all, is only 200 miles from Seattle by the route suggested. Tillamook or even Lincoln City would be a better target for your first day's efforts. One site that my wife and I found surprisingly enjoyable in this area was the
Tillamook Forestry Center a bit inland from the coast, but worth the detour.
That would set you up for Day 2 with more stops along the Oregon Coast, but a major stop at the northern California redwoods, using the
Newton B. Drury Scenic Parkway through
Prairie Creek Redwoods State Park and hiking the
Lady Bird Johnson Grove at
Redwood National Park. Then, rather than staying in Eureka which has a more commercial feel to it, try Arcata just north of there which is a funky college town with its own distinct vibe, particularly around the
town plaza.
On Days 3 and 4 continue to work your way down the coast. Now, while CA-1 can be a bit slow at times, I think I'd use it rather than US-101. CA-1 is the only way to get to great coastal towns such as Mendocino (the entire town is a state historic site) or scenic lighthouses such as that at
Point Arena. An overnight stay in the Bodega Bay area would set you up nicely for a final day consisting of visiting
Point Reyes National Seashore and still having time to cross the Golden Gate Bridge before evening rush hour, let alone sunset.
AZBuck
