There’s a reason more than a few screenwriting books or books about story allude to the idea of a voyage. Two immediately spring to mind - say John Yorke’s ‘Into The Woods,’ or Joseph Campbell’s, ‘Hero’s Journey.’ Physical journeys in film can be one of the best manifestations of a character’s inner world - their thoughts, fears, desires. The structure gives the filmmakers a clear beginning and literal end goal, a string on which to map out the story. The journey has the potential to show their transformation more cinematically than other story formats. The fact that the character’s physically move through changing environments, encounter new people and obstacles both increasing the stakes along the way is a great formula for drama and conflict. That conflict could be with the physical environment, the society they find themselves in or directly with other people along their path.