Brian,
Saving the Cumbres and Toltec Scenic Railroad, by the late Spencer Wilson, and published by the Friends in 2012, should answer most of your questions since it covers the history of the railroad from 1968 to early 2000. Unfortunately, copies are as rare as hen's teeth (time for the Friends to re-issue?).
For those who didn't know Spencer, he was a distinguished professor of history at NM Tech, was a much beloved member of the Friends Board, and he served as a NM Commissioner of the C&TSRR. He also wrote the book that made the original case for the two states to acquire the railroad. Clearly, a guy who made a difference.