As the nature of the film was low budget, the art department had to get crafty when creating the war wagon. It was strapped together with scraps collected from the main location. Rebar from the barn welded together for the cage on the front. The front bumper was a drain cover found in the back of the house. The roof wrack was an old fence frame found in the woods.
The shooting schedule for certain scenes had to be changed due to a snowstorm that transpired during the production of this film.
At the 37:27 mark you can see a movie poster in the background of the room Sarah is sleeping in called The Mailman staring Kalvin Kauffner. This is a play on the 1997 post apocalyptic film The Postman staring Kevin Costner.
The war wagon was a yellow school bus in an earlier draft of the script.