I think that the blank piece of paper can be linked to the theme of the journey in a couple of ways. All journeys begin with the unknown in front of them. Literally, each journey's start is a canvass where the protagonist who must undertake the voyage has to paint the picture or write the story of that quest. The blank sheet of paper represents the hero who must confront a journey in front of them, waiting to be taken and waiting to be born. The paper cannot write itself. Someone must write the narrative that the paper will hold. In much the same way, the journey itself cannot be undertaken unless a protagonist is willing and able to assume leadership in the voyage.
Within the contours of the paper can be hurt and joy, pain and elation, community and isolation. These narratives can be written on the paper and these narratives are part of the journey. The blank piece of paper is a symbol of all that is to be written. It is reflective of everything that can be, the hope and promise intrinsic to endeavor. In much the same way, the start of a journey contains such hope. Both feed into what can be as opposed to merely looking at what is. This would be how the profound meaning of the blank piece of paper is reflective of the journey.