You guys are good!  I don't know how I missed it, but I did see the La Dee Flats one on at least one older map.  The reference to the strip at Peavine was not part of the segments you scanned - it was in the last chapter of the book:

After re-reading this, it kind of sounds like they just used the spur road by widening it.  There are a few straight sections of logging road near Peavine that could have been used.