Ms. Mod,
Celebrity appearances are fascinating in a sense. How do you satisfy everyone? It is a tough thing.
I was wondering if your team ever thought about this: Why not make the barrier of entry a bit more steep so people can perhaps get a little more time with King?
Perhaps a requirement to buy the book and pay, say, $200, $300 to meet him might cause less of a crowd to show up. Also, no one under 18 would be allowed (bringing younger kids to such an event, especially now that his audience has most likely aged, seems counterintuitive).
This may sound awful, but it simply reflects the reality of a once-in-a-lifetime opportunity. It actually accomplishes a few things. First, it increases the cost to professional autograph seekers and helps to ruin their business model. Second, only people who really want to meet King will do it; the casual people who are doing it only as a lark will be discouraged from clogging the line. Third, the reduced line will allow for things like taking pictures and maybe talking for a minute or so. Fourth, your team has a great opportunity with the money. It could go to a local charity, or it could go to the staff of the bookstore; perhaps it could even go to one needy person/family in the town visited, or on the staff of the bookstore. The price to meet King could go up or down depending on how many people buy the book at the first couple signings. If a low number turned out -- say 80 -- you could also consider simply adding stops to increase the number of sold books; this would actually allow you to visit more bookstores.
In terms of taking pictures, one suggestion: when I recently attended a Dan Aykroyd signing for his vodka, he had a good way of handling it (not sure if his team does this all the time, though). As soon as you go up to him, he invites you to sit in a chair next to him and do the picture, doesn't even give you a chance -- you just hand your phone or camera (more likely the former) to the staff and a picture is snapped. I, being one of the only people on the planet who doesn't own a photo-taking cell phone (or any cell phone, for that matter), awkwardly shook his hand and said I can't sit down because I don't have a camera. I still wonder if maybe I could have sat for a moment, said a quick thing, then got up; that seemed too odd to do, so I didn't do it. Anyway, that was the second time I met him for a vodka signing, and I noticed that process was added. Believe it or not, the line moved quickly and smoothly. I did still, however, wish he had charged for the appearance.
One question: does King sign for everyone who shows up by the stated end time of the session? Aykroyd did. Then again, this is all by ticket, isn't it? That might be a bit different.