Mine's not a chewer, he doesn't really 'wolf' down his food for the most part, and the only kind of play he understands is chasing something, even if it's just me and him playing tag. Won't fetch, catch, tug, or chase anything that's not alive. But he will play by himself in the snow like he's on drugs. Other than that, your other descriptions apply. And his only loyalty is to whoever has the tastiest treat in their hand, even if it's a total stranger.
You'll have to put up some pics of the sled/wagons, so I can get an idea if it's worth attempting.