Thanks Brandon. Here's the first full on dirt test.
https://youtu.be/8sPC6El7xpk I'm only running 4 AA batteries (6v)because it was the only thing I could make up quickly to fit under the hood. If I decide to keep this setup I will add a few ounces of weight to the rear to aid traction. Even still I think it works fairly well and on topsoil it will probably work even better.
Reg