flightaware.com/live/flight/ASH17
I know these flights just shuttle around the islands, but getting the plane out here would be a long flight for one of these birds…hopefully there were no passengers on board when it came out from the mainland. Yuck.
Of course they ferry the aircraft to the islands. However, to say it would be a long flight is wrong. It wouldn’t be that much longer than a larger jet and, due to fuel requirements, it’s doubtful they would have more than 50% of the seats available for sell.
I dont’ mean that it would be a long flight from a time or speed aspect, that it would be a long flight for you if you were a passenger in one of those cramped seats 
But what did I say? It would be no more than 50% full so you would have two seats (or more) for every butt on the aircraft (except the pilots - they still get only one per).
If they are not ETOPS certified, and I’m assuming they are not, they would have to be ferried to/from the islands under part 91.
with ferry fuel tanks in the baggage or fuselage - most likely in the center holds for weight and balance
I was on a CRJ-900 from CHS-CLT last week that was full and needed all the bags moved to the rear cargo hold for W&B. Another annoying delay - the dispatcher dropped the ball on that one. . . good thing the captain caught it though . . .