Quite a number of people doing the same thing, so you can fight a little for work, but, like anywhere, if you are the best at what you do, you will always have work. Word of mouth is a big way of getting trades over here, so have a great reputation, prove yourself over here, the word will get around and he should be set! Good thing is you don't have to drive all over Brisbane or busy roads to get to work each day, the worst thing would be a ferry ride between the islands! Small hardware shops on both Russell and Macleay or Bunnings, closest is at Victoria Point on the mainland.
There is now around 4000 people living here so that gives you an idea of size and that figure has doubled in less than 7 years so I guess there must be some work here, I do see quite a few houses being built some of them have owner builder signs on them. what would he charge for an hourly rate for house framing? (might find him some work here)