Brendan Millett A nice quiet pal. Great views of the city and harbour. It would be a top place to be on New Years eve for the fireworks. It is very small but has fantastic views across main part of the harbour. It is surrounded by residential so you need to be quiet and it is not an easy place to find. Check your maps.
Burak Uslu As a none Sydneysider, I dont know how many amazing parks could you have. Reid Park opens info Mosman Bay. You can have a bite or a drink at the Rowers Club. You can walk along the harbour towards Tarango Zoo and enjoy some of the secluded coves along.
I highly recommend.