I have a couple of friends who are planning on travelling through Europe and i thought that you guys here may be the best people to ask some questions.
Their plan is to go from London to:
Paris
Backpack through Belgium
Maybe Amsterdam
Hamburg
Copenhagen
Berlin
St. Petersburg and Moscow
Prague
Vienna
Venice
Rome
Geneva
Back to Paris, then London.
Now here is what i'd like to know.
What methods of transport do you recommend? What is an experience that they shouldn't miss out on? What sites should they see, maybe not just the more famous ones? Anything else of note that they should take into consideration.
The Lonely Planet Guide to Europe is a good start (it's a big book but contains a lot of advice).
I think they will find that Interrail will prove to be the most economical (on the wallet) mode of transport.
One thing I would ask is how long are they going for because that's a heck of a lot of places to visit.
Lonely Planet used to also publish a guide "Europe on a Shoestring" - essentially the same as the other one but with cheaper stuff to do and places to stay. Massive book, about £16, but well worth it and still helps me on my travels to this day. The forums on the lonely planet website can also be really great, they had a website called the thorn tree or something similar used exactly for this sort of thing. I personally would recommend taking a detour to Krakow if you can, amazing city with the Salt Mines and the sobering Auschwitz nearby.
If you do post on travel websites though, be sure to give a little more information on your plans. I think they got a lot of people who want them to plan their holidays for them, and that can get up their backs a bit. Best of luck though, travelling is the greatest experience you'll ever have, bugger to anyone who thinks it's cliched!
From Brussels to Amsterdam DONT take the Thalyss (The red TGV Thingy) But the so called "Beneluxtrein". Bring you within 2 or 3 haurs to Amsterdam. You got cheap retour tickets for them, and doesnt need any reservations. (You got also something called the "InterRail" if i am correct.)