Zhouzhuang sits in Kunshan, on the Jiangsu side of the Shanghai-Jiangsu border. The most straightforward route from Shanghai is Metro Line 11 to Huaqiao (the last stop), then a tourist bus to Zhouzhuang — the total journey takes about 90 minutes and costs very little. From Suzhou, it is about 38 kilometres by road; direct buses run from the North Bus Station in under an hour.
Driving is possible but the parking area is outside the old town, and you will still walk in. There is no rail station in Zhouzhuang itself; the nearest high-speed rail hub is Kunshan South Station on the Shanghai-Nanjing line.