[Burkeman1]

They are disputed highly. There was a theory put forth by a rich Boston Yankee in the 19th century that the Vikings had settlements along the Charles River inland from Boston. He even had a statue commissioned of Eric the Red that still stands on Commonwealth Avenue to this day. The New Foundland settlement is the only verified Viking site in North America. The Minnisota stone is also highly suspect as it was dug up by a Swede on his farm.

It is verified that the Norse of Greenland visited North America often to fell much needed timber. And they may even have had extensive contact and trade with Inuit and Northern tribes like the Micmac. Some think they may have explored as far south as Nantucket, Martha's Vineyard, and Cape Cod.

[Spruce]

I don't think it is too far fetched to speculate Viking explorers made it to the great lakes, even further.