I haven't been for years now, but if you head north at all, the black flies will feast on you. Mosquitos can get bad too in some places. You will want some repellant with "deet" in it to ward them off. Depending on how remote you are going to get, some bear repellant might come in handy. We've really encroached on bear territory and so more troublesome bears can tipa campsite loooking for food as they've lost their fear of humans. You probably won't run into one if you make some noise treking, though it would be best to have repellant and not need it than need it and not have it.
Lastly beware of the smooth talkers on the Island, they will love you and leave you. A bad lot those ones.