Hi Bob: Welcome to HK Outdoors! Several ways to Lantau. I think the best way – tho not most convenient from Mong Kok – is to take a ferry from Central (piers in front of IFC building; with New World Ferry), to Mui Wo on east coast. If time not an issue, ride a slow – ordinary – ferry, upstairs ("deluxe"
), for best views as you leave Victoria Harbour, head out past islands.
From Mui Wo, could take a bus, such as the bus to Ngong Ping (inc Big Buddha).
You could also head to Tung Chung, on n coast of Lantau. Maybe take MTR, from Olympic or Tsing Yi stations. Or, there are buses; Kowloon Motor Bus has services inc E32, originating in Kwai Fong. From Tung Chung, are also buses to places inc Ngong Ping; also – soon – the Skyrail to Ngong Ping. And, of course, when you’re on Lantau my book Hong Kong Pathfinder will help with hikes
Martin