I would think it might be a little too early for the VReader. My daughter is just turning 4 and she has been a road warrior pretty much since birth. We take lots of long trips, usually just the two of us. I would say the portable DVD player is your best option, you can get one that's around $50-60, don't bother with one of the "baby" ones, just get a real DVD player and something that will let you strap it on to the back of the seat, I wouldn't let him hold it. (I always look for a DVD player that opens up completely flat so it will lay up against the back of the seat).
My trick is just to bring a backpack full of lots of new and very cheap books and toys (even happy meal toys work for 15 minutes or so!) and just keep a steady stream of things for when he gets bored. I usually start out just letting her hang out until she asks for something to do, I try to hold out on the DVD for a couple of hours and use it for when she's starting to get really bored. The color wonder sets and things like that which are mess-free are great for road trips. Also, you will have some nap time and snack time that will help take up some of the time too. And, plan in time for running around at rest stops occassionally - or stopping somewhere that has a playground to eat. I've had to get much more patient with my stops, but it definitely makes her happier in the car when she's had a few minutes to stretch her legs. Good luck!!!