what is significant about the guitar that christopher left with his other abondoned possessions?

Chris is completely abandoning the trappings of his former self. The guitar was part of his old world, which he felt, was a slave to materialism and illusion.Even though his guitar was very much a part of the charm that Chris possessed, he felt a hypocrite taking it. I think, from a practical point of view, it was large and difficult to include on his nomadic lifestyle.