Bus service between Athens and the Peloponnese is excellent—so good that you might consider taking a bus to your destination and renting a car locally, saving on tolls and high fuel charges. Take advantage of the English speakers at the ticket offices; they have at their disposal a wealth of information that is otherwise hard to get. The association of regional bus companies (KTEL) has no overarching website covering Greece; instead it is broken down into several regional companies covering areas such as Messinia, Arcadia, and Corinth in the Peloponnesse. Each, frustratingly, has its own website, of varying degrees of usefulness. It's easier just to call up the ticket offices, who can explain the connections you'll need. Within the Peloponnese, you will usually find English-speaking staff behind the desk in the stations in the larger towns; in smaller towns and villages, the local coffee shop often doubles as a ticket office. The service from Athens to Corinth and Patras operates as frequently as every half hour from 6 am to late evening; it takes only an hour to Corinth and three or so to Patras. From Corinth, you can continue west or connect for services to Nafplion, from where a local network serves the nearby classical sights, and south to Tripoli and Sparta, with connections or onward service to such places as Monemvasia and the Mani. From Patras, you can make boat connections or connect to buses to Olympia and other places in the southwest Peloponnese. From Athens, direct buses also run several times daily to Gythion, Kalamata, and Tripoli and at least once a day to Monemvasia and Pylos.