Absalom had asked that his unborn child be named Peter if it is a son. To me, the name acts as a reference to Peter in the Bible, who haad gained true repentance. This signifies that by naming his unborn son Peter, Absalom will have gained true repentance, showing a positive side to this ending.
The hill mentioned in the first chapter can have some realtion to Heaven, while the valley can have relation to our world. As mentioned in the last chapters, Kumalo has to go up a very tracherous path to get to the top of the hill. In the Bible, it is mentioned that the path to heaven will not be the easiest route.