I use canoes in my work and 220 pounds would be nothing to worry about.A typical modern canoe is rated at about 750 pounds and will handle much more.The explorers,trappers,traders,etc.used some canoes that would make ours look tiny.The weight in the bottom helps stabilize the canoe.Also a canoe is about the best thing for dragging weight across sand bars,etc.
I'll support the notion that the stone, if it weighs only 220 lb, could readily be transported in a canoe.
Is there any history, though, of canoe "skin-and-frame" technology among the Vikings? Might they have travelled by dugout, instead. Or actually hewed logs and constructed a plank boat? A raft doesn't seem feasible, since the trip would be upstream.
In any case, transporting the stone via water from Lake Winnipeg up the Red to within fifty-or-so miles of Kensington doesn't seem insuperable.
Lugging it on a sled those last fifty miles would've been the hard part.