I've done a modified version of this route. I like the parts through Snohomish and the Everett Marina (takes you past the Naval Base). But the last part is though the Interurban Trail. Yuck! Parts of the trail is essentially sidewalk and there's some awkward manuvering through traffic and the mall parking lot.

The only drawback for many is that it's not very hilly. I'm sure that many will want something a bit hillier.[Not me BTW, I'm the BIGGEST hill wimp.] Of course, the part through Snohomish could be rerouted to the hillier roads. Maybe for the longer route?

Anyhow, I got the cue sheet off the Seattle Bicycle Touring Club website. The last links on the website list some great resources for route ideas. Don't forget the Rondonneur's website for routes too.