Theater to the stage door: literally 10 seconds if you go really fast. If you take your time, about a minute, tops.

Pre-show: 12:30 PM for matinees, 6:30 for evening shows.

As you exit the main doors of the theatre after the show, the stage door will be immediately to your left--only about 10 feet! The key thing I've heard is to stay on the sidewalk (and not go into the street) to get the best chance to get pictures or autographs. If you're going to try to see the actors before the show, I think the official call for them is only 1/2 hour before show time but several of them like more time than that so I think I'd go an hour early anyway. Keep in mind most of them probably won't chit chat long then as they're beginning to mentally focus on the show. Have fun when you go!  We'll be eager to hear your impressions!