The Three Travellers

In this past chapter, I think we have really seen three characters emerge as the main "gang" that takes part in all of the travelling and crazy adventures: Sal, Dean, and Marylou.
Dean follows this lifestyle because he is simply crazy. In agreement with Ashley, I think that Dean has really not matured at all; in fact, he's gotten worse, and could no doubt be described as certifiably insane. It seems that this insanity is what drives him to live this crazy life of traveling, that he is simply in love with everything in the world and will not stop until he has met and "dug" it all.

As for Marylou, she embarks on this life of constant travel because she has fallen in love with Dean's insane love of life, whether she likes it or not. Thus, she needs to follow him everywhere, a constant part of his adventures.

Sal's motives are much more complex. It seems that he is searching for his own path in life, the lifestyle that will bring him constant content until he dies rather than short bursts of ecstasy followed by depression. He is presented with two paths he can take: the life of Dean, of insanity , wildness, and restlessness, or his numerous other friends/relatives, who have all settled down to a comfortable, stationary life. Currently, he is trying to live both of them, and often alternating between them, all the time waiting for an angel to pop in front of him and open the gates to heaven for him. I doubt this will ever happen though, and Sal will probably be doomed to live a hectic life of restless, discontented wandering.