Two of my favourite places we went to in Greece were Fiskardo and Assos. Fiskardo is a little fishing harbour right on the northern tip of Kefalonia, it was the only place that escaped the 1953 earthquake relatively unscathed, and therefore it still has a lot of it's original Venetian buildings. Assos is a beautiful little village at the bottom of a mountain in a little bay right on the ocean.
We stayed in the south by St George's Castle, and it took us around an hour and a half on the coastal road. Assos is on the way back to the south of the island from Fiskardo, and right by famous Myrtos Beach. One of the great things about Kefalonia is that everywhere on the island is free parking, apart from the harbour-front at Argostoli, which is 50cents an hour. So we parked up at Fiskardo, and walked down to the small town.