Ok, Al is using 8x6volt, that gives him about 30% increase in amp hours
Al can tell you how he fitted those extra battery's better than I,
but it appears to have a lift kit and larger wheels/tires, this adds to the distance it will go, but if you go too large it will bog down.
10" wheels should work with appropriate tires, that will cost $800 or so.
I think if you get a new pack and keep it charged all the time with the BM or solar, you can get even more miles, and the pack will last 6+ years.
We'll let Al chime in here with his more specific info.
