I don't know that area specifically but I know people who leave canoes along their route so they can portage easily.
I've found a handful in my travels around there too. I found two that had a trail cam pointing directly at them. We only found the cam because my wife was about to squat for a piss, and almost gave the camera a show!Wondering if anyone on here fishes this area. Found a canoe afloat jammed between some rocks. Appears to have been there all winter.