[Mr_I]

We powered all six wheels; the KoP drive train has a dual sprocket at the transmission, so you can get two of the wheels on a side powered easily. (Just remember to swap the spacers on one of the axles, I'd recommend the non-middle one, so the sprockets align better.) Then all you'll need is a pair of sprockets and a loop of chain to reach between the middle and the other non-middle wheel.

The only other caveat is to make sure that the wheels powered directly from the transmission must have the same size wheel sprockets!