I have not crossed that far up, but have been looking into it for our boat. For the captain, the route depends on where you want to end up, whether you want to stop along the way and weather.

If someone leaves in May or June, chances are it is to avoid hurricane season in the western atlantic. So if a boat left in May or June as a way to be clear of hurricanes, they might go to Bermuda to wait for wind. It would be too early to go further north than 39•N because of the ice.

The westerly winds dip as low as Nova Scotia by July, after the Azores high is established; before then the band of variables is much wider so the weather not so dependable. If you want to go very far north in Europe, it will be a struggle at the end because the clockwise Azores High is strong; wind from the West as far as Biscay and from the north all down the Portuguese coast.

Further north (Newfoundland to Scotland or Norway) you can follow the lows across below Iceland. North of Newfoundland you would have to cross the Labrador current, which may carry icebergs south.

I would depart Nova Scotia for Newfoundland earlier, like in July, if I planned stops in Greenland and/or Iceland, but still not depart Newfoundland before August. That way I would have plenty of time to wait for the right weather in Greenland or Iceland. I would try to arrive in Britain or France by October, but Scandinavia by early September.

Even if you were going straight to England, you still go a bit north because of the great circle route.

A pilot chart will show you winds and current percentages for each month. You can download June and September to compare.

http://www.offshoreblue.com/navigation/pilot-charts.php

Look at World Cruising Routes by Jimmy Cornell. There's the British Admiralty's Ocean Passages for the World, as well.

The captain will make the routing decisions. You only say yes or no to the voyage. Still, it's good to understand the issues and options before you commit.