I did this trip back in 88, I'll give you a couple of ideas.
First of all, you gotta do Mt. St. Helens. Absolute must.
Second, if you want to see why WA is called the "evergreen state", drive along the western side of the Olympic Peninsula, and stop in for a quick visit (day or overnight) to the Quinalt Lodge, and take a hike. It can be a short (half-mile) hike. the place is amazing, and well worth the trip. You're in the middle of a temperate rain forest.
South of the Columbia, along the coast, is a faithful reproduction of Ft. Clatsop. this is where the Lewis and Clark expedition wintered in 1806 and it was a highlight of the trip. the place is staffed with people wearing period costumes, going about the business of a typical day in the early 1800's. The kids loved it. they used to actually make real lead rifle balls, melting the lead over the old stoves in crucibles, pouring it into molds, but the park service employees recently told me they stopped doing that because of toxic issues. They still have demonstartion shoots using the old muzzle-loading flintlock rifles, though. The place is really a treat.
Lewis and Clark National Historical Park (U.S. National Park Service)
I second on the drive along the columbia east of Portland. Awesome drive.
Another beautiful drive; Hwy 126 from Florence (hwy 101) to Eugene.
My cousin lives in Sisters, a pretty sophisticated little town, for being in the middle of nowhere. One of the coolest drives we took was one of the roads going west from there. It drives right through the middle of a very recent (around 1000 years old) lava flow, and they built a lookout tower right next to the road, all out of black lava rock. VERY cool indeed. It's 2 stories tall, you can climb up on it. I've been to some lava fields in other places in the west, but none as good as this one. The road goes through some interesting scenic changes, from the highlands of the center of the state, through the volcanic fields, into the cascade range, and then down.
In Nor Cal, the coastal redwoods are beautiful. allow some time there.
Mendocino on the coast N of San Francisco is a model of a New England town. Cool to take a look.
If you have the time, the Skunk Railroad goes from Ft. Bragg to Willits. There is a break in the middle, the best leg, by far, is the coastal half. Gorgeous part of the state, they usually have some cool entertainment on board, and good snacks at the stop. You'll need a half-day, worth it.
So much other stuff to see on this trip, but those are a few of the highlights that we still talk about 20 years later.
Have a great time. We enjoyed this trip so much, we're going to do it again, probably next year.
This time, we'll not stop at Nanaimo on Vancouver Island, but drive all the way to the end instead.
Less than 10 days to go before we hit the road... and I'm a little bit worried about road closures due to snow cover around Mt Rainier and Mt Saint Helens. WA guys, any input about expected road conditions there in mid May? Still too early in the season to go through?
