Tai Po Market Station is on the East Line. Taxis are easily available from the station and cost $HK25 (@ $HK12 = £1) at the time of writing. Green minibus 28k runs up the hill from the railway station and stops close to the lay-by. Ask the driver for Tai Po Kau (pronounced How). There is usually a steady flow of taxis past the lay-by for return, unless it is raining.
The East Line connects to the rest of Hong Kong’s transport system at Hung Hom or Kowloon Tong.