I live right by the Boeing Plant in Everett and I haven't seen this place this busy in years. Everyday there is a new 777 (mostly Air Canada now) sharing the pattern with a 172. The tours is amazing and you might catch a glimpse of the 787. There is a new museum where the tour starts. It's not bad. You get to sit in a 727 and realize how lucky you are to have a glass cockpit. However, it does look like a real pilots cockpit.
On top of the museum there is an observation deck about 100 yards from the runway threshold. Perfect viewing location for watching the new aircraft launch.