Visiting Athens with kids of all ages is recommended since they offer many activities for children of all ages.
Baby Traveller is a baby equipment rental company based in Athens.
Greeks often go on day trips. Here are some destinations by car: Cap Sounion with the Temple of Poseidon, Corinth, Epidaure, Loutraki, The Archaeological site of Mikine, Nafplio and some destinations by boat: Aigina, Ydra, Spetses.
For a two day trip by car visit: Delphi and Olympia.