None of the responses so far look at the relationship between the boy and the man. And that is what the book, at its core, is all about. The relationship is quite beautifully depicted. And this is despite - and frequently in response to - the situation they're in.

If you accept the dystopic, post-apocalyptic setting, there are a few pitch-black, horrific events that will probably not go down at all smoothly. I've not read The Stand, and can't really comment about the events in that, but will say that as a writer McCarthy typically has more ability than King to make an event hit you like a ton of bricks.