CJ, I have no axe to grind, and don't really care who writes the history so long as it gets done, and done well. I'm a railfan not a historian, so it won't be me. I mentioned Spencer only because his efforts are well known.
My guess is a comprehensive history will require input from many sources, and needs to be a cooperative venture. And there will probably be conflicting points of view, all of which should be recorded. Those very conflicts are what make the story of the C&TS so interesting. I doubt that one "repository" will have it all. Much of it is still in the heads of the participants. And over the years many people and organizations were involved. That is why Keller's recollections (and Coker's rebuttals) are so important. And we need more of that.
Now would be a good time to start getting oral histories from those who were there.