I just finished up the additional buildings that go with the barn I have. Here's what I have now:
Here's the cow shed, and yes, it is pretty boring right now, but it's meant as a filler piece and not eye-candy. It could be a good building to dart around or hide in to get away from a ravenous zombie horde, assuming there isn't a ravenous zombie herd (of cows) inside.
The chicken coop with some more of the undead little cluckers. And there's part of Farmer John sticking out of the little chicken door...
A nice dog house for the undead pup-dog rounds things out.
I have enough terrain for some rural scenarios. Next up is to start working on more suburban and urban terrain.