Its not a stretch to believe both GP and BL planned and paid for their adventure together. The nuts and bolts of it are their individual goals. What did they want to accomplish and are those goals the same?
I seems she wanted to broaden her interaction with the world, while he saw the trip as a means of distancing himself from the world. He belittled her efforts for that reason, and it became a fiery contention between them. He just can't seem to get her to cut the societal cord, to leave all communication behind and become one with a frugal, lonesome isolation. That's just not her. She's not fully into the game and it sticks in both their craws.
For all the discussion of the where's and whens, the most important is the whys. The inner dynamics of two personalities hoping for more, yet clashing at the epicenter where they should comfortably meet. They go through the cursory motions, but they have this immovable obstacle. Once met, the sad result is physical. They're simply out of reasonable ways to overcome the glaring abyss of difference living in the hub of their wheel. Her innate embrace of this world and everything in it, and his complete rejection of it for the world of self. Tough stuff and a flashpoint when youth, emotional immaturity, inability of compromise and raging hormones meet.
MOO.