I had an 83 VW Rabbit Diesel... 45 plus miles per gallon on short form biodiesel.
I'd get waste vegetable oil, filter it really well and cut it 4 to 1 with Coleman fuel.
The little Bunny ran great on it. (Warm SoCal weather may have helped)
I never tried hauling hay bales but with the backseat removed I could fit a 55 gallon drum behind the driver's seat.
