I went to Oahu in 1999 and Maui in 2000.
The cost of living is high, but you're in paradise.
In terms of being homeless, why would you need shelter? It isn't like you're going to freeze to death there and there are plenty of places to get out of the sun.
99.9% of the beaches are free. The islands are small enough to not require a car.
If you have experience as a waiter, waitress or a cook, you have a job and a steady supply of food.
If you know how to scuba, you have a middle class job.