Jeff Levenson's job at the museum is mainly to obtains funding. He is on the road every week but he'll return your phone call I'm sure. The museum has an excellent engineer who has been a member and volunteer for maybe 50-years. I'm sure the $1M is a good number. Here's roughly what has to be done (I have no access to the actual cost estimate and work scope so this is an educated guess). Roughly a half mile of track with overhead has to be built. The museum can't run on Metrolink CTC track (note Merolink will eventually continue through Perris and turn east to go to Hemet).

A half mile of new track means detailed design, grading, drainage, ballast, ties, rail, line poles, guy wires, feeder wires, a half mile of copper trolley wire, all installed by a contractor with some volunteer help. There has to be a physical connection with the Metrolink track that also sees a BNSF local freight at least weekly. The Metrolink track will be CTC so I'm guessing the museum will need some special communications and other equipment. I'm sure there have to be preparations at the Perris Transportation Center (benches, signage, etc.). I have no doubt missed some cost items but I think I have outlined enough to show the extension will not be cheap. It's a big deal. Hope these thoughts help.