Hi Andrew,
It's good to hear that you and your girlfriend are planning a trip to Ireland. Certainly, using
public transport is a great way to get around Ireland.
I would say that the best way to get from
Cork City to Dunworley Beach would be to take a bus from St. Patrick's Quay (which is a 10 minute walk from Cork Kent Station) to Ballinascarthy, Clonakilty and then take a taxi the rest of the way.
As for getting back to
Cork City from Dunworley Beach, a taxi to Clonakilty and a bus from there to Grand Parade looks to be the best option.
Regards,
Eoin