I want to stay there at the end of September, how far in advance do i need to make a reservation for an ocean side room? Double occupancy, two beds.

Now. If you have specific dates, and want a prime room in the most beautiful month on the Central Coast, call now. If they cannot take the reservation this early - very unlikely - ask them when you should call.

I did mine a week in advance and it was cheaper, i guess it depends on timing or unsold units

ASAP