sorry!I've been there for a Christmas dinner/meeting, it's very cool. But, it's not open to the public as per say. However, I believe it could be, if you contact them and tell'em that a Cadillac Club or Group would like to rent it out for a night or weekend or car show. The working operation compares to a banquet hall.
here is a link with some pics:
I have sent out several e-mails requesting how we can access this museum for a Saturday. Greg Wallace who is mentioned in the joyride story has been transferred to Turin, Italy, I sent him an e-mail anyway.