This summer I'm driving the family to Yellowstone. That's going to be about 24 hours in the car. Instead of fumbling around with 8 - 10 DVDs in the back seat, I'm thinking about plugging in my ATV into a DC converter, putting that under one of the front seats, then running a component-to-3.5mm jack to the input of the 7" DVD player. Assuming the DC converter can support the ATV and I can find the cable I need, what am I missing about this setup?