Okay, I'm going to get dinged for this by the folks who hate touristy sites, but the Seattle Underground was the most fun tour I've ever had. I also loved Pike Place Market and just strolling around downtown Seattle. The Pacific Science Center (particularly the butterfly house) is wonderful. Seattle Zoo is great---don't waste your $$$ on Tacoma's.

Vancouver's acquarium and Grenville Island are fabulous.

If you get to Portland, try to go to McMenamamin's to see a movie and have a meal. Pied Cow is a great place for dessert for the kiddoes---in an old Painted Lady.

Also, Dave Carter and Tracy Grammer are FROM Portland. I don't know what their schedule is like, but you owe it to yourself to go listen if they are in town.

The Aladdin Theatre (which used to be a porn theatre) is the best venue in PDX for live music. Saw some truly great acts there.

Mt St Helens, the Columbia River Gorge are not to be missed.

Have a wonderful time. You are going at the best time of the year.