James Franco was cast as his hippie pot dealer that he goes on the run with .
Rogen was chosen to play the film 's protagonist , a 25 - year - old who accidentally witnesses a murder while delivering a subpoena .
James Franco was cast as Rogen 's hippie pot dealer that he goes on the run with .
Rogen was chosen to play the film 's protagonist , a 25 - year - old who accidentally witnesses a murder while delivering a subpoena .