Bridge
With the chain and hook, they dragged the four chosen logs up the hill, where the warriors got to work planing the logs to roughly the same thickness with their shovels.
It wasn't the most precise use of tools ever, but the logs split well enough when the enchanted tools hit them, and Sister Betty had managed to pick out four that were long enough to span the gap between the two hills without the need for any fancy joinery or a brace in the middle.
They were well over a metre around, which the driver assured them would be enough to drive the bus over, as long as he was careful not to give them too much of a jolt. But he had plenty of practice at that, since not everywhere that he had to go to recover teams was on a proper and improved road.