The traffic lights are right at the entrance to the "golden triangle" area. Kwan Yick Si Dor / Lam Chuen Sun Chuen will get you to the right place in taxis from Tai Wo- cost $30. The number 25A minibus or the 64K also run up Lam Kam Road from under Tai Wo station, cost $5.10 and $7 respectively. The 64K will take you up to Kadoorie Farm.
Mike can furnish you with details of the ridge walk... it's a biggie! I've been meaning to have a go at it myself.