which is very odd because we don't have even a slight mound of a hill anywhere near us.

Being a farmer we had scrap piles of enough stuff that I could have build a space shuttle. So I built dozens of them, even well into my teens I was building them.

Behind our shop we had a loading ramp. Maybe 3-4 feet high that we used to load tractors, tracklayers, onto flatbeds for transportation.. that was our 'mountain'. So my soapbox runs were of very short duration. We had to improvise.. so when no adults were around we'd tie length of rope to the front of the soapbox and the other end to a tractor, maybe a pickup, and then pull it around the shop yard. Many, many, many injuries. - JamesJM