I think Odysseus decent into the underworld is a metaphor for his life and that is life is that good right now and he is metaphorically descending into hades. This is really a decent into the underworld. Odysseus speaks to the shades of the dead in the underworld who are like ghosts of the underworld because the underworld is supposed to be a shades, scary, uninviting place to be.

Well in book 13 athene tells odysseus that she is the master of disguises and that she wants to disguise him before going to ithaca. She suggest disguising him as a beggar because people don't like to look to closely at beggars so it will keep in unnoticed. I think the disguise is a symbol of himself that is because he doesn't want people noticing him in ithaca because he was to noticed when he left originally.