I like riding up from the I-90 trail, up past the mall and the honda dealer, across I-90 using the pedestrian overpass past BCC heading towards the Mormon temple, then along that road, past THAT KFC.
straight a half mile or so further, then as you enter a suburban park just past the tunnel that leads under I-90, regaining the trail all the way to ride along to Westlake Sammamish near the traffic circle and school, then north along the West side of Lake Sammammish, to Marymoor park, then onto the Trail all the way to woodinville.
Least amount of road, and relatively light traffic except near I-90 along the feeder roads there.