Skip the previews: We thought that for his first time at the theater, it would be a good idea to skip the previews. We arrived just in time for the main event. That cut about 15 minutes off the sitting time. If necessary, leave the moment the movie finishes instead of sitting through the credits. This also helps you avoid any crowds at the end. Do whatever you need to limit the sitting-still and staying-quiet time.
Ease into the theater: We started out standing in the back of the theater, not even being able to see the screen at first. I let my son guide me about what he felt comfortable doing. After standing for a few minutes, we turned the corner where the screen became visible. After standing in that spot for a few more minutes, my son walked over and sat down in a chair. We were in!
I did not know if this day would ever come, but I could not have been more pleased with how it went. He sat beautifully and watched the entire movie. I think the prep really paid off. Not only was I proud of him, but I am so happy that we now have another activity that we can add to our list!