Let's Go, Lonely Planet, Rough Guides, Rick Steves are all good. Get them out of the library and see which one suits you best.

Basically at this point I see the trip planning as one big math problem. Say you have to spend $1000 for your airfare, that leaves $2000 on the ground. That's $95/day if you stay 3 weeks or $71/day if you stay 4 weeks.

You've listed 3-4 countries for your 21-28 days, that gives you only 1 week for each country, which is not all that long if you plan to visit multiple locations in each place.

Personally I would skip Greece but not because of 'horrible economic state', rather I simply think a 1 month trip in Spain, France, Italy is a plenty ambitious itinerary.

Remember the less you move around, the less it will cost you. Both the savings on transporation but also often you can get a better deal on a bed/room/apt if you stay a week in the same place.

Rail passes, or not. Again it's a math equasion. You need to know where you are going (or set up a few possible scenarios) and see if a pass or 2nd class point-to-point tickets work out the better deal.

One thing, Rachel, about your budget. It seems a bit low if you are going to be traveling to all your destinations. Just the airfare and train fare might run up to $2000.

The other place to look for accommodations for you and your friends might be AirBnB. It is a bit risky and people on this forum do not favor it, but you might be able to find some affordable apartments for the 3 of you.

what suze said... we were posting at the same time.

I think it seems like what I need to do is eliminate a few cities, and just focus on the major cities we'd like to visit. That way, we won't run out of money! :) Thanks to everyone for their wonderful advice! Should another question arise, I will be sure to post it on this forum seeing as how successful this one was.

Thank you again and safe travels to everyone who is planning a trip as well!

Both eliminating some cities/countries or shortening the overall length of your trip a tiny bit are two ways to make the budget you have work better.

$95/day is more realistic than $71/day (remember that is covering *everything* on the ground, your train tickets city to city & country to country, a place to sleep each night, local transporation if applicable, admissions, meals, miscellaneous expenses that come up).

First off I'd concentrate on finding a place ticket. That is by far your single biggest expense. You mention "many student flight discounts available". I'd pin those down asap.

If you can stay with friends and acquantances, definitely work that angle!! Besides the money savings, spending time with "locals" gives you a much more authentic taste of a place than being a tourist on your own.

Oh, another tip, Rick Steves has free podcast guides of many, many major sights on his website. They are actually really good and informative (not too dry to enjoy) and they are FREE :).