Hi Helen,
Thank you for your question.
Crowds are always a concern and as a parent we worry so much about getting separated from our kids.
There are a couple of things that we do to make sure that we all stay together. We explain to the kids that everyone is excited but they cannot run off. We tell our kids that "if you get lost, stay at the ride you were at"
I also tell them that if they did get separated to go immediately to one of the Cast Members and tell them that they are lost. Disney has systems in place to help reunite kids/parents. The child will be taken to the lost children room.
Your girls will have a great time at all of the parks! The
Magic Kingdom is a must do! My kids all love going to
Epcot as well!
I would book character dining as well. My girls love
character dining, eating with Mickey and pals or having a special meal with the princesses is so memorable! Make sure you pick up autograph books!
Wishing you a very magical vacation!
Carrie