B.J.
I agree with Elena S. My son was a terrible traveller when he was an infant. He would scream for the entire trip if he wasn't asleep. We also put a mirror up which helped, but the clincher was when we put him facing forward. Although "experts" suggest keeping them back facing as long as possilbe, we switched my son as soon as it was possilbly safe (at the suggestion of my mother-in-law) and he's been a happy traveller ever since!
Have you thought of possibly setting up a portable DVD player on the back seats so he has something to watch when he's still facing backward? It can show anything from educational DVDs to home made DVDs of you and him so that he can watch himself. If I would have had one of those when my son was little, I would have tried it!!
Good luck!!