I have friends who have spent summers on Baffin Island for scientific research and archaeological studies. It is very bareen, but yes there are hikes you can do. If you plan to get away from civilization (such as Pond Inet at the top of Baffin Island) you'll need lots of preparation. Polar bears live up here, my friends who worked there all had to learn to shoot a rifle, just in case. Kayaking is a great option as well. It's expensive to get to, and expensive to get around. There are "expedition" ships that often do tours between Greenland and Baffin Island for very high prices. The distance from closest point of Baffin Island is around 200 miles across rugged sea, but it is much further than that to/from any points of civilization. Just "hiring a boat" isn't an easy option. You'd have to organize and chater a boat in advance, I believe. Much simpler to explore Baffin Island, then fly from Iqaluit, Nunavut to Kangerlussuaq, Greenland. Sounds like a fun trip you're planning!