The original script was written by an Academy Award-winning writer, but wasn't used because it would have been too expensive to film. Moreover, the revised script was still being written as the episode was being filmed.
Some dialogue from "W.G.O.D" plays over the radio two minutes into the episode (from 2:07 to 2:50 to be exact). That's Gary Busey as the voice of Reverend Nolan Powers (his performance in this episode would be considered uncredited). In the "W.G.O.D" this audio is heard at the exact same time (from 2:06 to 2:50).
All the special effects were done live on the set by shaking the camera.
Tom Skerritt improvised the moment in which he gives the middle finger to the Hitchhiker as he drives past him.