It appears that she's visiting Club 33. As for what goes on in there, anyone can find out. The waiting list is ten years long. There's a dining room with a checkerboard floor. A bathroom that has a bathtub because it was originally intended to be used by Walt. There's also renditions of popular Disney tunes played, some of which can be found online. I don't think there's anything secret or weird about it. I even saw a video of a guy who had snuck in and did some filming. It just seemed fancy and a place where rich people sit around being rich.