The advice here is good, but it may be a little too safe.
If you want an adventure, use an atlas and truck stops like Loves or Pilot for snacks, a nap or shower. These places are rad, super safe and clean (the stigma is bullshit). It can be a little more expensive and take a little longer, but there are a LOT of great and interesting people in the US and it's pretty much the safest it's been since the sixties.
Also, I recommend favoring AM or FM radio (in that order) to hear some wild stuff out in the boonies.
Edit: Make sure your car's lights are all working so the cops don't waste your time. The US may be safer than it has been, but the cops sure ain't.
Way of the road.