I've now read, cover-to-cover and back and forth, Marti Anderson's The Mining Camps. A detailed review is coming, but for now I have just one word to describe it. Awesome. As in awe-inspiring.
With all the references to surveying and in view of my basic ignorance of the technology involved, last week I interviewed John Mellblom, surveyor who works in the Utilities Engineering department of the city of Boulder. He gave me a very helpful initial tutorial on the basic logistics of surveying a route, including the tools, the technique and the underlying geometry/trigonometry.
I've found a nice little booklet on the "ghost towns" of the mountains of Boulder County, and a 1902 map of the roads. The booklet tells some fun vignettes of history; the road map demonstrates well why a railroad was needed.
Finally and most importantly, two weeks ago I road by bicycle the south Y of the route (Eldora branch) from the Peak-to-Peak, at Glacier Lake, to Boulder. Today I road the north Y of the route (Ward branch), from Gold Hill Road/Station to Boulder. From Sunset on down it's the same ride, of course. Pictures, observations, learnings to come.