traveling with another family that is on a different schedule. We're planning on going to WDW with my BIL & SIL and they're daughter. We have one son and at the time we go, my niece will be 5 and my son will be almost 5. They are consistenly always late. I don't want to spend my whole trip waiting around for them. For people that travel with others on different schedules, how do you handle it?