The Snyder Trucking business is a reference to Zack Snyder, who remade Dawn Of The Dead. The Savini residence is a reference to Tom Savini, who was responsible for the make-up and special effects in Dawn Of The Dead and its sequels. Having a high cardio level will give you more stamina for things such as running, climbing walls, and melee fighting.
This process takes a while, but since the opening section of the game does not contain any tough zombies (plus day cycles do not occur until after you reach the church), this is a great time to build up the cardio stat. Repeat this process to continue to increase your cardio level. When stamina is depleted, stop and rest until it completely refills. When you are in the parking lot of the Ranger Station, either run to the left or right while turning the camera in the direction you are running. At the start of a new game, go to the 'safe zone' of the Ranger Station (the circle on the map where zombies cannot spawn/respawn).
