I have cut out the background panel and the gear box which will house the shaft and cams used to create the action.
I like to leave the front of the gear box open. Having the gears, cams and wheels exposed makes the finished piece more interesting.
People like to see how the motion is created and when they turn the wheel they not only see the action, they can see how the mechanism works.
In this photo I have cut out the cart (not pained yet) and I am checking the fit to make sure both pieces look good on the base. I am also working out a way to hitch the cart to the tractor.