The key is to plan ahead and know your limitations well enough to know how you will manage each. Being in the car for an extended period of time; then work around that to come up with a travel itinerary that maximizes fun and minimizes stress. Also, planning gets the kids involved in everything! They're invested in it because they made the decision.
The latest trend: family vacation planning. The idea behind it is to encourage families to take the time and save the money so that they can meet all of their travel goals. Preplanning is about getting value and saving money; like you would for college. Some families struggle to save for their family vacation and this destination may be a once-in-a-lifetime experience with the family.