I think the crowned Princess you're talking about is the Cinderella fountain at MK. When you go through the castle into Fantasyland, it's right on your left. When you bend down to take a drink from the drinking fountain, it looks as if the statue of Cinderella is being "crowned" by a crown painted in the mural behind it. It also makes the people drinking from the fountain look as if they are bowing to the princess. The key under the mat is at MuppetVision in the queue. It's at a door somewhere on the right of the first room you enter. The rope is neer Indiana Jones Stunt Show, but I've yet to find it.