I overheard a friend make this recommendation - though you have 16 minutes for each mile, try to train to finish each mile in 15 minutes. That way, you automatically have some padding. Of course, the excitement will make you walk faster, but the faster you are, the more time you have for pictures!
Good luck!
As for myself, I booked a room for the Princess Half weekend, but haven't signed up yet. I got sick before running it last year, and am scheduled to run the
Disneyland Half and the Wine and Dine Half, and I think I want to get through at least one of those before signing up for another race and jinxing myself!