I love boats.....were I to get a large enough one, i.e a yacht, it would work. For water, you just need a solar collector. Long distance yacht racers use them. Food wise, theres fish obviously, and then you would only need freeze dried food and staples such as rice. Plus, if you are a good enough sailor and the boat is in good nick, it is unlikely to sink.
If it was only a few people it would be great.
The getting off would be less of a problem if you chose somewhere which was out of the way and not heavily populated. Easter island would probably be good.