That was great. My next door neighbour and I were both hot wheels fanatics when we were young and we put together a couple of tracks that were multi-floor through our houses that actually worked (even more ingenious than this one), but this was fun to watch filmed.
As for the onboard, CanadaDarrell had an RC plane that he had equipped with a fingernail sized wifi camera he bought direct from China (probably stolen US military tech
)...I bet this is something similar.