This is one of the most beautiful places in Greece.
Elafonisos is located in the south of the Peloponnese.
This is Simos beach, this is the best of the best beaches...
Sorry my friend 
Generally there is no club or nightlife, But it has great restaurants and cafe...
Does not have many sights to see but the beauty of the sea and the colours of the sky will enchant you,
"Ta nisia tis Panagias" is a great restaurant with an amazing view...
The island is offered for relaxation and not for nightlife..
Ιt is better to go with your girlfriend than with your friends.
it's an expensive island, but it's worth it.
Of course it has camping which is very cheap.
If you go with friends, it is better to go to the camping
If you go with your girlfriend it is better to stay to a hotel.
This site is a great guide to the island..
http://www.elafonissos.gr/el/elafonissos.php
I hope you will also make a stop in Athens..
Have a nice Sunday...