I'm split. I used to be able to think purely in a personal intuitive way but psychoanalysis has begun to enter into my appreciation of things.
I can't help but see the father and mother as the frame of this story. The father is dead and they are carrying his luggage all around India on a journey which will eventually end with finding their mother. However, the dead father reappears symbollically as a deadly tiger that is haunting the nunnery where the mother is living. At the end the boys decide not to go back home but to remain for the rest of the time they intended to stay but in order to catch the train they have to leave behind all of their father's luggage which they've been carrying around which bears his initials. Basically the story here is one of the psychotic whose self isn't held together firmly and is as fragmented as the train is shown to be during a sequence when each room holds a different person and different style (or the ship in Life Aquatic, etc..). By creating a different name for himself (letting go of the father's name) he can hold himself together. I think the same thing is going on with Bob Dylan (Robert Zimmerman had so many different people and styles in him). With someone like Maddonna the process would be the same but rather than holding together a bunch of personalities her change of styles represent serving fashion and staying on top which is a protection not from mere guilt of not being anything but the psychotic fear of the Other behind the scenes who can devastate one's reality (aliens, demons, etc... when the break occurs and leads to delusions).
Though this psychoanalytic backdrop seems feasible to me we can say that the enjoyment of the film is never found there.
But the real story is in the childishness of the characters.