f you enjoy a little bit of freedom and privacy, I recommend Duff Reserve as it offers views of the Harbour Bridge and the spectacular Sydney Tower Eye and the nearby skyline.
Though it is a little bit hard to access this place, there are rarely people there as it is not near the main street. It is on Wolseley Road at Point Piper. You can take bus 324 or 325 which will stop near Rose Bay on New South Head Road. Walk up along Wolseley Road for around 11 minutes and you can find the entrance on your left hand side.
Walk down the staircases and you can find the pavilion with a table inside, a bench outside and a piece of grassland. With superb views of the Sydney's harbour side, you can spend half day here just enjoying the view, listening to the sea waves and enjoying some food that you have brought along.
It cannot be accessed after sunset and before sunrise and can only be accessed by staircases, so plan your schedule before you go there.