My proposed itinerary for you.....

Wed Oct 31...Your flight gets in stay in Vancouver
Thu Nov 1...Vancouver...evening drive down to Seattle (stay in Everett)
Fri Nov 2....do Boeing tour, do museum of flight...evening in downtown Seatttle
Sat Nov 3...day in Seattle.....drive down to Portland
Sun Nov 4 day in Portland for Saturday market, Japanesse garden
Mon Nov 5 Columbia Gorge, wineries
Tues Nov 6 Day along coast near Cannon Beach and Astoria (Lewis and Clark sites)
Wed Nov 7 Drive up stop in Olympia and Tacoma
Thu Nov 8 Day in Seattle..explore the other parts you have to drive through like Ballard, Fremont...
Fri Nov 9 ????
Sat Nov 10 Vancouver
Sun Nov 11 Vancouver


Im not sure when your flights arive and depart.


Also....

Not sure if this is your taste or not....

In Seattle under the Hwy 99, Aurora bridge is the fremont Troll.

Not sure if you get this in the UK...but there is the discovery show on the alaska fisherman called deadliest catch. Many of them are based out of Seattle so in the ballard locks there are a few tourist things there. You can tour one of the retired ships.

Also in the Fremont/Ballard area there are few city parks that give you the scenic view of the seattle skyline with mt rainier in the background on a clear day.

The itinery can be adjusted based on the westher.