Correct and sometimes correct. Back when I was a CM, that was my attraction. And you're correct that there is no track for the canoes. And you're also correct, for the most part, that it's the guests that provide the propulsion; however, from my experience, most of the rowing power comes from the two cast members on each canoe, one in front and one in back, because the guests tend to not put much muscle into it.
I say that there is no way that there is a track and the canoes are most definitely powered by all of us guests that are rowing.