Spent 4 months there myself back in 1992/3, at Shag Cove, almost self sufficient, apart from diesel (for the generator) being brought in by Chinook, food, mail, personnel on R&R (for 4 days each week) and TV videos by helicopter.
We got our water from a well which run low in December so we had to use the fork lift tractors with plastic water containers to go to the nearest river and collect water for the week.
4 months doing rock climbing, walking, cycling, archery, sailing, canoeing and windsurfing, it was almost a holiday, if the family had been there.
We were lucky however, as it was the milder months weather wise.
You would be better off with 4 or 6 wheel drive and a well insulated vehicle during the winter months... good luck.