What is special about the narrative structure in Cormac McCarthy's "The Road"?

Cormac McCarthy's The Road begins
in medias res ("in the middle of things") but after the apocalypse
("series of low concussions").  The novel borrows narrative elements from science
fiction, travelogue, horror, and bildungsroman (novel of
education).  The narrative structure is, more or less, a walking Socratic seminar--a
series of questions (by the son) and answers (by the father).  Irony is achieved in the
seriousness of the son's wanting to know that they're "the good guys" and the father's
patient reassurance that they are.  The father must not only protect the boy's life,
but--more importantly--his faith and innocence.

Action is
determined by the father's two bullets.  He must decide whether to shoot a cannibal or
kill himself and his son to avoid being eaten.  Worse, he has taught the boy to use the
gun on himself, an unthinkable act.  Death is inevitable for the father, we know, so we
are desperately vested in the safety of the son's life.  He is like Adam, Jesus, and the
Holy Grail: the world's faith and future generations depend on his
survival.

Even though the narration is told in third
person, it is clearly from the father's point of view.  We know about his bad dreams,
and he has flashbacks about his wife.  The time is present day or future, hard to tell.
 The father says he hasn't kept a calendar in years.  We do know that the boy was born
into the apocalypse--he has no memories before it.  We also know that his mother
abandoned them by committing suicide.  And we know that the father will likely die from
inhaling the foul air from the fallout.  So, the father must help the son find a sense
of hope and faith in a nuclear winter filled with
cannibals.

About half-way through the novel, McCarthy
foreshadows his ending when the boy thinks he sees another boy.  In the end, after the
father dies and boy is rescued by the man with the shotgun, we realize that this other
family has been following the father and son the entire
novel.

The turning point of the novel, however, is the
son's decision to go back onto the road.  The father, had he been alive would not have
done this, and he had taught the boy to hide at all costs.  The son's act of faith in
confronting the man with the shotgun leads to his and humanity's salvation--although,
technically, the ending is open-ended and salvation is implicit.