There have been a number of excellently researched and written books about the narrow gauge RRs in California. On the NCNG alone I have 3 books that cover that line to a more than trivial degree. In addition to Best's volume, there are "A Tale of Two Cities and a Train" by the late Juanita Kennedy Browne, and George Turner's "Narrow Gauge Nostalgia". There is also "Oil Lamps and Iron Ponies" by Shaw, Fisher, and Harlan, which I hope to acquire some day.
Other n.g. lines covered in complete books include the Pacific Coast, the South Pacific Coast, the North Pacific Coast, West Side Lumber, the Southern Pacific Narrow Gauge, the Pajaro Valley, the Diamond & Caldor, and the Michigan-California lumber operation. I wouldn't be surprised if there are several other complete books as well. There have also been a number of excellent compendium volumes each covering the lines I've already mentioned along with many others. The list goes on ...
These lines are fascinating and the books well worth digging up.
Happy hunting, Glenn