I also couldn't help but compare the two books. The evil in No Country For Old Men wasn't as rampant as the evil in The Road. And the sense of justice in the former was missing in the latter. In The Road, evil was inescapable.
On another note...
Clearly the father's caution was justified and probably saved both of their lives numerous times. However, I found it interesting that throughout the book, while the father appears to be the 'wise' one, teaching his son lessons and giving him powerful advice along the way, it seems as though the son was wise beyond his years. Not only did he pick up on figures of speech and vocabulary that a child normally would not be able to use correctly, but he also took his own perspective on the world.
I think the difference between the father and the son comes down to their opinions on human nature. As we discussed for a brief moment in class, a post-apocalyptic world is one that, in literature, tends to reveal true human nature. I believe the father thought people are inherently bad, while the son believed people to be inherently good. And this is not always a naive assumption. He probably saved his own life by trusting the man he met at the end of the book. Despite his assurance that the 'good guys' still existed in the world, I was under the impression that the father didn't really believe that. He was simply trying to instill hope in his young son where he had lost all hope of his own.