Yes, Dean is a guide for Sal. Who ever said you couldn’t lead by negative example? Sal certainly picks things up from Dean, watches his movements, his driving, his sexual interactions. Just because Sal chooses not to go along with Dean’s wild life choices doesn’t mean Dean isn’t a guide. It just means Sal would prefer to not die at one-hundred-and-ten miles-per-hour on the highway.
Wait a minute…you can’t have two mentors! Can you? Yes. As a matter of fact, we’re even thinking about having three. So about Carlo. He has "The Voice of Rock." He is thoughtful. He’s a poet, for Pete’s sake. Just because no one listens to him, just because they stare at him blankly or giggle at his serious questions doesn’t mean he doesn’t fit the role – an unsuccessful guide, perhaps, but a guide nonetheless.
Old Bull Lee is the wise sage guru guy. He has experienced everything, read everything, tried everything, and now he sits around and teaches. For the first time, Sal and Co. actually sit down and listen. They openly characterize Bull as their teacher and are willing to learn. What does he teach them? Oh, important life skills like pulling nails out of wood, holding cats over bathwater, and throwing knives. He does, however, teach Sal about visions, and about listening to them and learning from them, which Sal tries to later do in regards to the Shrouded Traveler and the old man with white hair.