Would be good to know where you are actually travelling to for your cruise. Newfoundland is a big place, and while St Johns on the east side is the main city (Corner Brook being the only other one really), Port au Basques right at the opposite end of the province is the main ferry port to Nova Scotia and the rest of Canada, which are sold as mini-cruises in their own right.
St Johns is not that far from Europe, only about 5 hours - the Air Canada A319 makes the round trip to London within daylight.