ferry

Hey all,
I am about to be studying in Athens, Greece for the next 4 months, and I am wondering what the best forms of travel are between Athens and European countries such as France, Italy, Amsterdam, Poland, Austria, and Germany. Because i would only get to travel on weekends and some weeks, is it best to by a eurorail pass or just go trip by trip? Is flying better in some cases?

Also, how does the ferry system work in terms of international travel?

Thanks so much!
-Katherine W.

I am traveling through Europe her soon. I found that the cheapest flights from America to Dublin. I am going to bu a Eurail pass also. So my question is if I fly to Dublin, then stay for a couple days, how to I get to a city such as Amsterdam? I saw that the train is in Ireland but, do I need to pay extra to take a ferry to the closest city on the mainland that has the Eurail? How much would that cost?