Interrail, Eurailpass and the like may sound like a great deal, and oftentimes they are, but it is always worth checking the small print about validity. And if your proposed itinerary includes rail travel in central and east European countries, you may well find that locally purchased tickets turn out to be a very much better deal, especially if you have access to the internet and can comb websites to identify current special offers.
Some examples we have come across recently suggest that North American agents exploit US travellers' fear of high European prices and sell European point to point fares in the US retail market that seem truly outrageous.