Niggle's Journey

One allegorical element that I saw was that of Niggle's "journey". There are a few different meanings that I thought might be. My initial thought was that his journey, after the imprisonment, was like his death. The way that I interpreted it was that after the imprisonment, Niggle was sent to paradise, like he had died and was sent to a heaven-like place. I also thought that his journey might represent that of adulthood. Before he left for his journey, he basically had freedom, as one does when they are a child. Once he went on his journey, he was sent to work. I know that in the real world that work does not have to be as harsh, but Niggle did not have the freedom he once had. He was "forced" to work until he was basically worn out completely.