From Southwest Harbor, ME to Newport, RI -- that had a variety of seasonal "help". From the ice cream parlor/coffee shop in SW Harbor which had Russian college kids (supposedly on a "exchange" program, though I don't know if there were counterparts in Europe?) who were working at a shop which is open for maybe 90-120 days a year. I'm not sure if there would be shop there but for such programs. I don't get the sense of that the owner of that little shop was making that much money.
As for Nantucket, a few years ago, I was told by a long-time resident that I know that the local Hardware store flys its staff in every morning from the "mainland" because they can't afford to live on the island. They can't keep there staff without providing them a way to live.
I find Martha's Vineyard more interesting as an island. It's more hetrogeneous in all kinds of ways: economic, ethenic, racial, religious, etc. Really more reflective of America. (But enough of this stuff...Let no true expression of emotion go unpunished. ;^)