Looking at your fluffer, would it be all that difficult to make those wheels pivot? You have square standards on each end...could you insert shaft/pipe and mount the axles on them, then have a pivot arm on each end with crossbar tying the tops together, and add a cyl and mounts to swivel them? Sort of like a wide combine steering axle on high-crop steroids!
Looks like a hyd motor by one wheel....driving the pickup? If it interferes, mount it right on the upper draper shaft like I did?