I have no experience with your expo, buy I have been to the Road to California, and there is no room for a stroller. I go on Thursday and Friday, because the weekend there isn't even elbow room, let alone a place to sit down.
Maybe, if they have an area for eating you could take turns tending to the baby.
One rule I do go by when I go to shows - never buy anything the first time through. Bags tend to gain weight as you carry them along and possible to set it down and forget it. So I make notes and go back - if I can't remember the item then I didn't need it after all.