The town is a living hell if you are searching for parking, so take only the hotel with own parking places. We stayed at such a hotel - Nidimos Hotel (booking.com), chose a room with a sea view and a balcony, we recommend.
Both modern and antique cities are interesting primarily for their location. Not everyone likes to walk on the ruins, but here the ruins are in a beautiful place in the mountains. And we know that everyone loves the mountains.
From above you can see that the most preserved objects are theater and a huge stadium. The city held the Pythian Games - the second most important games after the Olympic Games.
Find here opening times and prices.
Getting there: By bus from Athens from Terminal B (map). Travel time is 3 hours, the ticket price is about 17 euros (find timetable here). Buy return tickets in Athens. From other cities you need to go to the city of Itea and there take the shuttle to Delphi. If there is no shuttle, then 17 km by taxi, it's about 20 euros.