I also read with interest the Mercury News story linked from AlphaRoaming's log entry, which describes how he found a trove of gravestones along this route to the bottom. From the story I'd expected them to be all gone, but no -- soon I came upon the former home site where they must have been, and there were still many gravestones left along with other jumbles of cut stone. It definitely makes for an interesting site in the middle of the forest. This blog post by AlphaRoaming has some great pictures of some of the historical markers that were found here and subsequently moved, some back to their original sites.
Gravestones
I had trouble picking up the former road again from the home site, but eventually found it about 20 feet left of the gravestones. It's a bit of a challenging route down to the Canyon Trail, but not overly so.
You're looking for a camo'ed soda bottle preform hidden near the gravestones.
Note that as of 05/2017, both the spur of the Charcoal Road trail that leads to A Secret Trailhead Redwood Pair and the first part of the unnamed road/trail from there to the bottom are not shown on Google Maps, only on OpenStreetMaps.
Congrats to Team Io-Honu on their FTF.