As usual, VdM gets it in one. For all its beauty, The Road is a simple work. In fact, it's so simple, as yorky has already noted, you often want to add more than what you're given. But that's a trap, so don't fall into it. From my experience, the first crack at The Road cannot be repeated. I wouldn't risk going through someone else's eyes for the first time.
From the works of his that I've read, the characteristic lack of punctuation is the only opening McCarthy allows his readers to interact with his characters or even the text as a whole. Otherwise you take what you're given as he doesn't care what you take away from what he's written. The Road is no exception. Unless you trust the guy on the audiobook, it might make a huge difference to your experience, if the guy reads a thought as dialogue or fails to recognize that the same character continues to speak.
As to other McCarthy, I would go back to the near beginning, to Blood Meridian; Or, the evening redness in the west. All his other novels answer for why he's spilt so much blood in this novel.
Spoiler
For example, why he keeps coming back to the Apaches and/or scalping
. The writing style is less polished in comparison to his other novels, but in terms of scope, it is his most ambitious.
I see Tommy Lee Jones is involved in filming Blood Meridian, which gives me some hope. After watching Inglorious Basterds, I wonder what Tarantino would have done with McCarthy. You need somebody like that who is comfortable with violence to film this novel.
I love No Country for Old Men but give it a little time if you've just read The Road otherwise it will seem like nothing. I happen to think it is a beautifully understated meditation on violence. McCarthy at his most restrained.
