Anyway, I got to idly wondering what use a museum is that's not open to the public, and why it would also be the largest independently owned and operated mausoleum, so when I got back I did five minutes' research on the web.
Wikipedia redirects "Edison Museum" to the Thomas Alva Edison Memorial Tower and Museum. But the song is clearly actually about the Edison National Historic Site although it's referred to on both pages.
The official page doesn't seem to mention anything about it being haunted, or a mausoleum. It does say it's closed to the public during renovations, but it also says that renovations began in 2003, which post-dates the song.
So… I'm still confused.