I was wondering what they may have been doing that far west, ---
It's very easy to explain if you look at a globe and imagine Greenlanders trying to go south along the coast of America.
-- The most direct southerly route from Greenland is into Hudsons Bay and up the main north flowing river, -- the main branch of which ends up being the Red River of Minnesota, where the runestone was discovered.
So, they came into Hudson Bay, to the SW shore, up the rivers to Lake Winnipeg, then South, against the current all the way UP the Red River, all the way to the SD / ND border and were moving EAST or South or SE..
Actually, if they made it all the way to the headwaters, they actually came almost straight East from there, to where they buried the Kensington stone..
Which on foot, would probably be about 10 days journey..
If the travel was done during the spring, they may have been able to take some advantage of the massive flood plain to travel..
Spring flooding would also explain their description of burying their marker on an island
That part of Minnesota is fairly flat, and dotted with many lakes.. not quite as much as farther north and east, but still well covered..
Sunken Civ's post in #31 notes that 8 returned, in 1364, to Sweden..
Considering those 8 survived and returned, one would expect that colonization of some sort would have occurred...
Reports of a land that vast and rich would have driven people crazy with desire..
There should have been veritable flotillas of Swedish and Norwegian ships headed to America (Vinland)..
Yet, this didn't happen...
Just more conjecture, more questions..