Be Sure You're Compatible
You and your friends might have a lot in common when you're just hanging out at playdates, but you could have completely different vacation styles. If your friends insist that their children turn in for the night by 8 p.m. while you have an open bedtime policy on the road, you're going to be miserable by Day 2 of the trip.
Before committing to a joint vacation, test the waters and take a mini trip together. Go on a daylong outing to the zoo or the children's museum to see how well your families mesh. If you butt heads on everything from what to do to where to eat, better to find out now than after you've caravanned four hours in a minivan.