I agree with Big D. completely. The Chuckanut Drive is probably one (many others too) of the best drives in Washington State and has even been mentioned as one of the best in the Continental United States by some reports. I just took this drive all the way to Winthrop about a month or so ago and it has me wanting to go back. The drive I took was with the local BMW CCA club and it was about a 500 mile round trip.
There are also so many mountain roads and passes that makes for a great one day or more trips.
Also you may want to take a drive to Mount St. Helens. The drive up is great and definitely not boring. There are many places to stop and read about what happened in the location you are stopped at. The scenery is breath taking too especially on a nice warm sunny day. Once you get to Mount St. Helens observatory (the road ends) you can take in the sites and history of the great mountain and its demise. They have really cool hikes you can take there too. Hope this helps and stay in touch on the board. Lots of great info here and the people are the best of any board around....