Peteski is correct. It's no simple task, but it wouldn't be any easier with a Kato lighting kit, I don't think. The Rapido LEDs are fed by two 1.5v watch batteries in series. Disconnect these and you have the same two power attachments as the Kato. Both would require current limiting, a bridge rectifier, and preferably a cap to stop the flickering. The benefit to the Rapido light kit is that you own it and it's already installed in the car. Both would also require power pick up. Either Kato trucks or power pick ups from Streamlined Backshops (he makes them to fit the Rapido truck). The power pick ups add a bit of friction. The Kato trucks roll as smooth as silk but you would need to modify the mount and the correct style may not be available if that matters to you.
It definitely requires some effort.
Craig