I traveled the route down the #511 South Fork yesterday. I found maybe a half mile of blazed trail east of Lower Rock Lake but from there to the Roaring River just a nice bushwhack that followed, I'm sure, the general layout of the original trail. Unfortunately the climb out of the canyon on the 517 was almost more than I could take. I posted a verbose account of this adventure for my latte swilling friends on the Portland Hikers BB that can be seen here:
http://tinyurl.com/r256noA thanks to Donovan Harding for providing some back story on the 511 and the mention of the F. Alton Everest book. While slightly out of the area of interest here, back in August I posted a trip report of a recon of the north end of the Plaza trail near Welches, the Arrah Wanna, and the northern end of the Hambone Trail at it's Salmon River trail head here:
http://tinyurl.com/nshamj--Paul