My ambitious plan HELP please

[manna]

So me and my best friend are planning a month long trip through Europe for next summer late May to June. I have planned out quite the list of cities to visit within that time:
Start Cork, Ireland
London, England
Paris, France
Brussels, Belgium
Amsterdam, Netherlands
Berlin, Germany
Prague, Czech Republic
Vienna, Austria
Venice, Italy
Rome, Italy
Geneva, Switzerland
Barcelona, Spain
End Madrid, Spain
So that's 13 cities in one month which I know is quite a bit but I want to see so many places. I plan on traveling by train and using night trains when I can. I would also love to go to Greece if that was at all possible. So any advice anyone has on places to cut out or an option on getting me to Greece I'd be open to hear it. I also plan on having about 4000 and going budget all the way with hostels and self catering. Can I do this or am I crazy?
FYI- I don't plan on spending too much time in Paris or London but I want to see them. The cities that are real must sees for me are Brussels, Amsterdam, Berlin, Prague, Rome, Madrid and Barcelona. Santorini would be my ultimate goal if I could make it to Greece.

[madamtrashheap]

Welcome to GFE, manna.

It's always tempting to try to fit everything in on one trip, just in case you don't get back, but it's highly likely you will get back as once you've started travelling, it kind of becomes a habit! ;D

As you've listed your "must see" cities, perhaps you can build your itinerary around them and save any other places you don't make for the next trip. Instead of flying to Cork or London, look at flying in to say Brussels or Amsterdam and out of your final city on an open-jaw ticket. This will save any backtracking, so look around for any good deals on open-jaw tickets, you may even have to go to a travel agent for help on this one.

In terms of an itinerary, here's a suggestion (number of full days in brackets):

Brussels (1)
Brugge (2) - this is a quick train trip from Brussels and well worth the stay
train to Amsterdam (2, or 3 with day trip)
fly to Berlin (check Air Berlin) (3)
train to Prague (3) with a stop for a few hours in Dresden
fly to Athens then connect to Santorini (from Rome check Olympic, from Athens check Aegean Air) (2-3)
fly from Santorini, back to Athens, stay 1 night for time to see a little of Athens
fly to Rome (check ) (4-5 if doing day trip to Pompei)
fly to Barcelona (2-3)
train (or cheap flight if poss.) to Madrid (3-4 if doing day trips)
fly home

As you can see, that will take the better part of a month and still give you time in the places you really want to see. If you still ahve a little time left at the end, you could always fly from Madrid to Paris, spend 4 days, then Eurostar to London for a few days (depending on any day trips) then fly home from London instead.

See what you can find flight-wise and if the new itinerary suits your plans or helps you see what you really want to see.

[manna]

Thank you so much for your suggestions. I still have a lot of kinks to work out. I do have to fly into Cork because my friend is doing a semester study abroad there and we are meeting there to begin our trip.
Also, I tried looking up some of these flights and they are looking really expensive. Could you recommend a website to use to find the cheapest flights? Or I've heard about some kind of global plane passes kind of like the rail passes if you know anything about that.

[WillTravel]

I understand you want to fly into Cork, but if you get a much cheaper flight elsewhere, even to another city in Ireland, it can make sense to spend a couple days where you land, and then proceed to Cork. But that all depends on prices and timing.