You will start your ride at a parking area at Chapman Landing and end on Route 47 north of Pittsburg and Vernonia. The trail follows an old logging road along the Scappoose Vernonia Highway. It is rough in some places and I would only suggest mountain bikers attempt this. This trail has been under construction for the past 5 years or so and the hope is to extend it to Vernonia to connect it with the Banks-Vernonia path there. I've provided a link to this guide with a VERY DETAILED tour of this rugged logging route that you really should click on before riding this.
The southern trailhead is on Rte. 30 in downtown Scappoose.
Guide photo provided by Mike "LeafSlayer" @ Flickr.