When I just had 2, a 3 year old and infant, we took the stroller and baby carrier. She spent a lot of time in both, but the stroller was a necessity for all the stuff we had to lug around between the two of them - baby food, diapers, extra clothing, etc. Memorize where all the baby stations are before you go, as they are wonderful. While in line, I often kept her in the front carrier and just adjusted it, so she was still in it on the rides. We waited while the other two rode the safari, as we were advised of the rough ride, but I'm sure they would have still let us on if we wanted. My advice: do what's best for your child, and give the pediatrician a call before you go to see what your little one should and should not do. You might be surprised.