The interurbin does fade in and out at different spots but it is onto user friendly streets. It is hard to follow sometimes until you have been over it. I have ridden on it from Everett to 125th quite often. To get from the trail to Paine Field go north to the next road beyond 128th which is 112th. Get off after you go under 112th and head west. It has a bike lane and takes you right to Paine Field. I've gone that way before and its much safer then 128th.