To get to Ao Bangbao Baech by road you need to drive to the Grand Lagoona Resort, They charge 100baht per person on entry and this is refunded if you have a meal in their restaurant, the rooms here are in the 2,000baht to 6,000baht range per night.
When I went the beach was absolutely deserted, nice and clean and defineatly no touts to disturb you.