Train watching spots - Seattle To Everett

[Nedsm]

I have a grandaughter in the Seattle area who is becoming an interested train watcher at a young age.  I would love for her to be able to see the SP 4449 & UP 844 locomotives during their May 19 trip.  Could someone provide some ideas on some good locations for viewing the train so that I could forward them to her dad?  My preference is for areas between King Street Station and the Everett Station.  Thank you.