When? - Rates change after April 15 at most places.
If you rent a car, figure $40-50 per day plus $20 for license. Public Ferry round trip - $80.00 for two should cover fare and all the departure taxes.
Now, where to stay, Shoal Bay East is good, but there is nothing open at night.
Meads Bay is excellent - many restaurants and places to walk, you would not need a car.
Rendezvous Bay is great - very nice beach - a few places to walk and low to high end places to stay - not sure if they will rent for one night - what is your room budget?
Ellen