I saw the show tonight and I'm pretty sure it was sold out. Hathaway was fantastic, as was the set design and the special effects. I did think it got a bit long in the tooth by the end of it and I wasn't a huge fan of the actual ending but it was very solid with Hathaway giving one hell of a performance.
As for the "stage door," I asked an usher where to go to get her to sign my Playbill. The usher told me that she wouldn't be signing but she was kind of snarky about it and I kind of took it as she rarely signs (if at all anymore). Who knows, that's just how I personally took it but from her body language and the way she said it, it doesn't seem like it happens often.