Yeah, La Mesa. I had opportunities to run trains there on weekends (no formal sessions though) for several months back in the early/mid eighties, and it was a great experience. Truly dedicated guys back then.
One of the best decisions they made was to skip ahead uphill to model the Loop itself, so that the original members could finally see it with their own eyes. Then museum director John Rotsart retired some time back, and I imagine Paul Lubliner* has contemplated it as well, as have many others there.
[* Paul was the man behind "N&G Signals" and later "Highliners."]