This story, the first and last third of it anyway, had been bouncing around in my head for years but the "Gomer" concept was actually an afterthought. Th original idea was for just traditional(Ramero) zombies and demons. The idea for the gomer didn't actually hit me until I was writing the scene where John wakes up in the barn loft and sees the farmer and the cow. I didn't originally plan on the farmer being a gomer. It was one of those eureka moments where I jumped out of my chair going "Holy shit... that's freaking creapy as hell..."  Not that I am a great writer it's just that being a lifelong fan of the genre I knew immediately that I would have loved that concept had I read it in a book years ago. Thanks for the question!