We covered this part of the Peloponnese last summer. The ancient sites are well documented in various guide books and we particularly liked Epidavros and Mystras. Naplion is well worth visiting and the fort above the town is spectacular. If you take the road towards the fort but continue straight ahead instead of turning right (to the fort) you come to a long sandy beach which is one of the best in the region. You also have the Saronic islands just offshore, we loved Hydra. If you have time to travel a bit further a boat trip through the Corinth canal or a visit to some of the Nemea region wineries is really worthwhile.