I had the common Magic Music Days backstage experience (where I saw a bunch of old Submarine Voyage props, a Peter Pan's Flight ship being worked on in a warehouse, and the cool towers from which fireworks were launched for the former Believe... show). We got to walk behind the Fantasyland Theater, past the Storybookland Canal Boats, and behind Pinocchio's Daring Journey/Snow White's Scary Adventures to get to the stage where we performed.
Also, once on an extremely busy day I was corralled backstage behind Main Street on the Space Mountain side. It was neat to see the old administrative building and the backs of all the Main Street Buildings, which look so plain from the back. The Mad Hatter was also taking a break with Alice, and it was strange to see him not wearing his big green hat.