Community Transit provides bus service from Mill Creek to downtown Seattle on routes 412,414, and 435. See
Community Transit
A very perfunctory glance indicates that they take a little less than an hour.
Mill Creek schools are in the Everett school district, which is a much better district than you might expect, but the district's test scores are as high as they are because of the schools in Mill Creek.
All of the schools in Mill Creek have much higher test scores than the state average, and parent ratings on greatschools.net say that Mill Creek schools are very good, particularly Mill Creek elementary and Cedarwood elementary...