All in all, great idea, but I have to go along with Xeno... how many sets of "pack animals" and "crude carts" are we really going to be using?
More than likely, I'd refer to my 3 B resources. (Bits Box and Balsa wood).
After all, a couple of "Near Future Armed Civi's" and you've got your armed guards. For a more "Apocalyptic" look, use the tattered "clothing" torso from a Zombie, a little knife work to add the other torso section or simply a head swap, then back to the "N F A Civi" box for just the right weapon.
I have to say.. I think WF in its own way.. already has this covered.