You are all mostly right in places
Boeing Field: A public airport owned by King County, named after Mr Boeing, Boeing the company still use it for test flying and delivery of it's aircraft
Everett: Builds the heavies in the fleet 777,747,767,787
Renton: (also in Seattle area) builds just 737s
Long Beach: Far as I know it's only building C17s now days (but then they have to build other military types somewhere.. eg F15,F18,AH64 Apache etc).
Longbeach is also home to their simulator guys
I personally think Boeing field is fairly detailed already by default standards, so I've never felt the need to go look for sceneries sorry..
Edit:
Boeing's defence business locations