I'm going to play some more devil's advocate
Forgetting whether the C&TS has the money or not, is there truly a demand in Chama for six operable locomotives? (I don't know, I'm just stirring the pot). Sure, I suppose it would be neat to have an operable K-37, but do the ridership numbers necessitate the additional motive power? If the answer to both questions is no, then why spend so much on something that is, for all practical intents and purposes, completely unnecessary ? In a day and age when many couldn't even tell a steam locomotive if it stared them in the face, I can't see very many riders being able to differentiate a K-36 from a K-37 to care whether one runs or not.
Money may be the root of all evil, but if you want to survive, you have to play the game. Museums/non-profits are just as vulnerable to fiscal mismanagement as any other organization, and if the controlling ideology. How many outfits can one name where the railfan mindset was the controlling ideology got them in a rut? As Russ mentions, Golden Gate Railroad Museum learned the hard way. Even the state-run CSRM wasn't immune (then again, neither was the rest of the state). It's too bad that so many, from a museum's Board of Directionless to the politimbasiles on Capitol Hill, just don't seem to exercise the same prudence and care when spending others' money as they would with their own.
This all isn't to say rebuilding a K-37 could never be justified. What if one of the current operating fleet is found to need work in excess of the cost to put the 493 back in service? From an economical perspective, that scenario could certainly justify parking a 480 to bring out the 493. That's how the railroads would have done it back in the day. And hypothetically, if the 493 had decent running gear but a bad boiler and the 492 had a good one but was beat from the saddle down, there could have well been have been a kitbashing.
I would hope the last 18+ months of economic erosion have served as a good lesson about the dangers of living beyond one's means simply because they thought they could afford it at the time. There was a time when I was a far more idealistic person when it came to this sort of stuff, but age (no competition with Russ, though!) and 3-1/2 years of working on these old beasts will totally change one's perspective of what it truly takes to keep them around.
Just serving some food for thought.
P.S: Russ, I'd bet my shiny nickel that T&P monster burns more sitting on a spot fire all day than either 2-6-2T at Niles Canyon does in a month's worth of run days!