This is the easiest way. After crossing Langzhong at Luohu Port, go to Hong Kong Port and buy a ticket first. It's for tung chung station. 48.5 yuan. You don't need to buy a ticket when you transfer. Buy a ticket, get on the bus, get off at {Jiulongtang Station}, go ahead, change to the subway and get off at {Taizi Station}, then change to the Tsuen Wan Line and get on the bus to {Lai}.