There's been a lot of flatbed trucks loaded with hay, thanks to a granny gear, a hand throttle, and a bungee cord on the steering wheel. My son used to do it that way all through high school- - - -all the driver did was get the truck pointed the right way, locked the steering, and then joined the rest of the crew bucking bales. At the end of the field, he did a 180 and they repeated the process.
Jerry