The Lantau Trail is a 70km circular trail beginning and ending in Mui Wo. It's divided into 12 sections ranging from 2.5km to 10.5km, some of which can be done alone, others which must be hiked together. While a few sections are relatively flat, others are among the hillier (and most spectacular) hikes in Hong Kong.
Sections 8 and 7 (in that order) – Shek Pik Reservoir to Tai O – are a long but relatively flat walk along Lantau's southwestern hillsides and down into Tai O fishing village. You'll pass a postcard-pretty beach and, with a quick 30-minute detour, the ruins of Fan Lau Fort and a Tin Hau temple. If you time it right, you can have a sunset seafood feast in Tai O before catching the bus back to Tung Chung. Plan for five hours.
To get to the trailhead, take the ferry to Mui Wo and catch a Tai O–bound bus. Get off the bus just after Shek Pik Reservoir on your right.