Norse longships do not look like they were be good for raiding or trading at all. Every recreation I have ever seen requires it to be practically filled from bow to stern with people rowing for it to even operate, and there wasn't any below-deck storage for goods or money. So where did they keep everything? Not even just trade goods or stolen things, but even food, fresh water, medical supplies? Stuff to make a trip lasting longer than half a day?

Of course it was versatile for shallow rivers or the sea, but the ship itself seems completely impractical for long voyages, especially for the weeks or even months-long trips that would eventually lead to the New World.