The Hunter Valley is about two hours' drive north of Sydney on the M1 Pacific Motorway, turning off at Cessnock or Branxton. Driving is by far the most practical way to visit — public transport to the valley exists but is slow and limited, making car hire in Sydney a better option than the train-plus-bus combination.
From Newcastle (about 40 minutes to the east), the valley is even closer. Newcastle Airport has connections to Melbourne and Brisbane, which gives visitors from other Australian cities an alternative to flying into Sydney. Some operators run day tours from Sydney by coach, which is the sensible option if you want to drink freely at the cellar doors without worrying about driving.