In terms of how would you best portray a larper in terms of film, I think a good sequence would be a three-shot: you start with someone playing a get-together game of baseball, zoom in to his eyes, do a quarter turn around still focused on his eyes, then pull back to reveal that an image of him in a big stadium during an MLB game. Cutaway to a girl practicing three-point shots, zoom in to her shoes and the line, then on a dribble, follow the ball to the hoop, where, as it drops through, you sound a buzzer and pull back to reveal a college ball game. Then, cutaway to a kid in costume hiding in some bushes, and a group of people in tabards escorting someone who looks tied up. Kid jumps out, slow-mo in midair, change the angle to follow his weapon striking the shield of one of the escorts, revealing a full-production costume and more "realistic" barbarians and such. Voiceover would be something like "We all like to pretend. Sometimes, life creeps in and the world seems insurmountable, so we all escape to a place where we can be kings and heroes.