From the North trailhead turn right and ride a couple of miles on a busy highway with no shoulder until the trail resumes on the sidewalk at 172nd (the road to the airport.) Continue on the wide shoulder of 67th. Somewhere after 67th curves under Highway 9 the trail resumes on the railroad corridor through downtown Arlington. Just beyond Division (one of the ways to drive to SR 530 and Darrington) is the intersection with the unpaved Whitehorse trail.
I think that the money has already been approved to extend the paved trail north from Arlington to the Skagit County line.
Once the trail is completed to the Skagit County line it will hook up with the Skagit County Centennial Trail.