My daughter spent the few years of her university time in Newfoundland so I was back and forth quite a bit. If you do go back the time to go to Gros Morne is time well spent. There are lots of birds and moose that are too tame for my liking. They walk within ten feet of people regularly for the couple of times that I have been there. You can take the boat trip up the lake which is nice but it is quite a walk from the interpretative center to the dock at the lake but there are lots of photo ops in between.
You don't say what your intersts are specifically but if you are into birds then NFLD is a godsend. There is Cape St. Mary's
which has tens of thousands of Northern Gannets which you can get real close to. These two were taken there.
If you go in mid-June or July you can get plenty of opportunities for Altantic Puffins. Go to either Elliston or Bonavista and you can shoot them from shore. There are lots of boat tours that claim to get you close to them and I took one but it was a small boat and rough making shooting very hard. Shooting from the shore at these two places is quite doable if you have at least a 100-400. This one shot at Elliston where they have Puffin festival each July.
If you get there earlier in the year, say mid-May you have an excellent chance of getting to see lots of icebergs. This depends on how many calve off the glaciers in Greenland. One year that I was there, there weren't very many but the next summer they were everywhere. You stand even a better chance up near Gros Morne. There were some just outside the inner harbor at St. John's. I went to a small fishing community on the edge of St. John's called Quidi Vidi and dangled some cash to the fishermen who were struggling at the time and got one to take me out for a couple of hours. Although he wouldn't get as close as I would have liked (yes I know they can roll) it was still a great day.
I've been through all of the Canadian maritime provinces and Maine as well. Newfoundland is still my favorite, it really is a photographers heaven. They have wildlife, scenery and very unique architecture so you will never have to go far to find something new and interesting to shoot. Even in the middle of winter I always found something to shoot though they do have some violent snow storms there. I haven't been back for a couple of years so I may make the trip down there again.
. We are going to spend most of our time around the Booth Bay Harbour area with a trip to Bar Harbour. Last time we were there it was so foggy at Acadia national park we could not see past 100 feet. I know we were on a road. 
