At the Overlook, the highway and the wire trail part, as the wagon road from Chanticleer to Rooster Rock essentially followed the wire trail to the riverbank below...
From Rooster Rock, the trail apparently continued eastward along the river bank to Latourell, Bridal Veil, Warrendale and beyond. From Latourell eastward, it is certain that the highway intercepted the trail at many points.
The road from the old Rooster Rock Cannery to the Chanticleer Inn site is still intact (not counting I-84), contrary to some reports. This route is NOT the route of the old Sandy River to The Dalles Military Road, it follows a different path through the area. The most recent research I've seen claims that the military road did run down this drainage between Chanticleer and Crown Point, but most the Rooster Rock Road was not actually on its alignment. Traces of the old Military Road grade do exist down there, though.
The whole thing is definitely walkable. Drivable, probably still, if not for the gates, the last time I was there. However, about 8/10 of a mile down there is another gate, and that may be what they are referring to. Officially, the road is not open as a trail but, except for passing over the UP land at the tracks, I do believe that it is all public property now.
Rooster Rock Wagon Road / Wire Trail - March 21, 2014
http://www.portlandhikers.org/forum/viewtopic.php?f=8&t=18677
Bushwhack below Crown Point 2-27-2014
http://www.portlandhikers.org/forum/viewtopic.php?f=10&t=18251&hilit=Bushwhack+below+Crown+Point
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