Stanron: "my understanding is that if you stick to the northern hemisphere getting back is easier than getting there."

Depends, east from L'Anse aux Meadows to Bergen is over two thousand miles but one would have waypoints along the route. A month is making good time. A slightly shorter route direct from Greenland was made several times a year in different eras, depending.

On the other hand going west at the 65th parallel one may be completely out of sight of land for only about 20-25 hours. By keeping Snæfellsjökull, Iceland dead astern and sailing just north of west it's barely four days to the Skerries off Kulusuk, Geenland. The ancient eastern seaboard colony at modern day Tasiilaq is about another day coastwise. With clement weather the east crossing can actually be a bit of a let down for first-timers after the odyssean build up in their history texts.