Dead Rising

Marathon Runner

You will likely get this without even trying but I will tell you a couple of ways to move around the store quickly.

1) Skateboards, great for when there is no zombies around and you can tuck it away in your inventory. You can get a skateboard in the Paradise plaza across from the roastmaster in the 2 floor sports shop. Use this wisely because without books it can only take like 3-4 hits and it will break.

2) Cars (what you will use to get 53,594 zombie kills, definitely recommend going for that first). You can get a red sports car in leisure park by heading to the parking garage in between the north plaza and food court. You can obtain a delivery truck when in the parking garage taking 2 lefts when entering. Lastly there is a white car below the Paradise plaza which you need to drive to using the other vehicles if you didn't obtain the maintenance key. The last vehicle is used by the convict's which will net you an achievement if you kill them and take their vehicle.

3) Motorcycle 1 appears in the North plaza while following the storyline. The other Motor Cycle is by the red sports car.

4) Quickstep mixed drink. In the beginning of the game you can keep grabbing coffee creamer (looks like chocolate milk) from the security office and mix it with the orange juice in Paradise plaza. Once you get this you can increase the effects by obtaining the survival book only after finishing the mission Hatchet man and obtaining the key. Once you obtain the key it will be in the locked area to the left of the hardware store.

5) Bicycle. There is one in the entrance plaza to the right of the entrance in the camping store. This is faster than the skateboard but you cannot tuck it into your inventory.

So if you want to go out of your way for this achievement grab the vehicles and start driving!