Just beat Level 4 like this. Basically, first $500 goes to Salvage yard, then just spawn 5 shovel men each until you can max out your salvage yards. Next is one trailer park so you can spawn 10 shovel men.. this should be fine until you have enough to get the farmhouse. When you can, summon a YeeHaw Mob and as many Angry Farmers as you can (at least 5, ideally 7-10 shortly). This should be enough to give you time to get to a Preacher, though I honestly beat it without even needing one.. just massing Angry Farmers and YeeHaw mobs. If you can get a bunch that are grouped right outside the base, it shouldn't be too much trouble from there. Game time was like 7:11.
 "Arkandian Crusade"){kind=icon}
 "Zombie Trailer Park"){kind=icon}