Current Back Seat Ent/DVD options, 1st gen DC

I'm planning a road trip and I have a 4.5 year old. I am looking to keep her entertained.

I know they have cheap set ups that can be built into the truck (headrests or flip down)

I also considered just using a portable DVD like the $100 Phillips model BestBuy sells.

http://www.bestbuy.com/site/Philips+-+9%22+Widescreen+TFT-LCD+Portable+DVD+Player/9832597.p?id=1218180677517&skuId=9832597

With the portable, she can use it on an airplane or take it to another car.

I have an x-box 360, but she doesn't now how to use it yet. So that may not be worth trying to incorporate. But someday, she will be able to use it.

 

The Phillips one can be taken on a plane now here's the catch it states it plays 5 hrs off battery but only on the dimmest setting and min volume setting and I'm sorry but where did u find cheap built in? Or maybe ur definition of cheap isn't like mine lol