K.L.
My 2 year old never watches TV except for the car. Not because we don't let him as much as he's just not interested. However, when stuck in the car for long periods of time, the DVD player has been an absolute lifesaver. We usually let him watch 1 movie, then either stop and get out for a little bit and let him run around (esp. any fast food places that have a playground area) or turn the TV off and tell him it's time to take a nap. We always make sure to bring his favorite stuffed animal and he still loves having the pacifier. We don't let him have a pacifier at home or day care anymore and use it as little as possible while on long trips but it does usually buy us another hour or so of peace. Other then that, I'd say your on the right track. Just little bits at a time and get as much driving in as possible while they sleep.