Rather than Cloverdale Lumber Company east of Quincy, I believe that you mean Clover Valley Lbr. Co. just east of Portola.
There were still a few artifacts out there in the 70's when I was hiking the ROW in contemplation of doing a book. I doubt if much is left although it is quite easy to follow the grade for most of the way. Start @ Hawley & continue north past the east end of the airport up Mapes Canyon past the summit to the old site of Crocker Tank (should be marked with sign). You can continue further out to Camp 13 where 2-6-6-2T 4 exchanged her empties with loads brought out from Camp 14 by 2-6-2 8. Both engines are still around and have operated since the railroad was last used in 1957 (as Feather River Lbr. Co. for that year).