Chip in for a sitter! I can only speak for the Expo in Cleveland, but it can be an overcrowded stampede. Even when strollers are allowed there are crowds trying to get into the booths and I've been slightly shoved and bumped by quilters trying to get a better view.
Always ask at the admissions booth if photo's are allowed - very often they aren't, and never in the vendor booths.
Know what you're planning to buy. If you have a project in mind and a colorway you won't spend as much.
Hope you have a great time.