B.S.
I would also give them something to go along with the tickets thats related.
For crayola factory, a box of crayons, markers and such.
For Port Discovery...what looks like a children's museum. Maybe some type of science or craft kit. For the youngest it could be something really simple...maybe even some kitchen food from a farm or something of that sort.
Also might be fun to incorporate a special outfit they can wear at these places, if you wanted to go to that length.
The tickets sound like a great idea by the way!