You can get to Waiheke on the Fullers Passenger Ferry, It is usually a 35 minute trip from Downtown Auckland to Matiatia Wharf on Waiheke. Some boats also call in at Devonport, Auckland on the way, so add an extra 10 minutes for this route.
Once at Matiatia wharf, walk briskly to the bus stop just outside the terminal. Chapel Hill is on bus route number 1;. As you board the bus ask to be dropped off at the Golf Course on Onetangi Straight. Push the buzzer, to stop the bus, just as you pass Tantalus.
You can also hire cars from Matiatia wharf and even can hire electric bicycles.
If you wish to bring over a car, book well in advance on the Sealink Car Ferry. This leaves from Half Moon Bay, and also takes foot passengers. There is no public bus from Kennedy Point, where the ferry arrives.