The Peloponnese is separated from the mainland of Greece by the original isthmus [Isthmia] and the Corinth Canal. This is the main gateway to the Peloponnese from Athens. There is a great [toll] motorway from here all the way to Kalamata which has opened up the region to holidaymakers from the mainland. Most tourists lazing around the beaches in the south don’t come anywhere near here.
There are some wonderful sights such as Ancient Corinth, Acrocorinth and Ancient Nemea which do not get crowded. When we visit this area we stay a few nights in Nafplio afterwards which works well for us.