When Ruby and company are driving away from the gas station , considering their head start it is not likely that Cate could have nearly caught up to the van while on foot as she was shown to have done when the van turned onto the road.
At 49:30, when Ruby goes away after seeing her parents from outside the window, there is U.S. Flag flying, but it is heavily torn. In several countries, flying a torn national that is torn is considered a national disgrace and there is even criminal punishment for the person who is responsible for a torn flag to be flying.
It's explained that all adults moved to the big cities. And really, the places the kids go are so deserted they can roam about freely in broadest daylight without keeping guard (which is why they're surprised by a bounty hunter - twice). Yet Ruby's parents still live in the same house.