Bkfitz - there is an ONB run shuttle from Gun Creek. I think they charge $20 or so per person for it, but they take you right to the beach club. You can find out timings when you make your lunch/dinner reservation with ONB.

I believe it runs at set times. When we were there they walked around the club towards the end of the afternoon to gather up any stragglers and make sure they didnt miss the last shuttle home!