Bilbo begins this important journey without the sense of purpose that the dwarves have. He awakens late and the fact that the dwarves have already left allows him to second guess the commitment he made the night before and revert to his comfort-loving hobbit ways. Bilbo's worry that he has forgotten his handkerchief is a last remnant of his hobbit life; after he begins his journey with the dwarves, such concerns seem irrelevant. It is significant that the dwarves agree to give Bilbo a share of the treasure they will reclaim, because greed is a dwarvish trait and they have difficulty sharing.
Gandalf continues as a tutelary figure in this chapter. His role is to impart wisdom, directing Bilbo to realize his potential on this journey. He drives Bilbo into honoring his agreement with the dwarves despite his misgivings. Gandalf shows up unexpectedly at Bilbo's house and disappears later in the chapter. He continues throughout the journey to appear and disappear almost without warning, an indication of his powers.
You begin to get some sense of the geography of the journey to the Lonely Mountain as the group passes through hobbit-lands and Lone-lands. As they travel east and approach the Lonely Mountain, the way becomes increasingly difficult and the landscape becomes bleaker and less familiar.
