W.N.
Kids have it harder but safer now than we did. When I was young, what were seatbelts? There weren't any in the rear of the car. As unsafe as it was, we had the run of the car and could work out our energy. Thank goodness for car seats and restraints now. But that is why I don't feel guilty about a little DVD babysitting. The world is a different place, if we were forced to sit still strapped in when we were kids we would need DVD babysitting too. Also think about buying some brand new toys so they are fresh and exciting and wait to open them at different times during the trip. I find the travel magnadoodles and aquadoodles great for the car also.
If your kids are prone to car sickness make sure the DVD player is suspended above their heads so they can see the horizon in their peripheral vision. Very Important if you don't want vomit all over the place! Have fun!