re: Planning a trip to Europe(Barcelona and Amsterdam)

One thing I can say is you have nailed mostly great cities there. I loved Barcelona (just do all of the Gaudi stuff like Parc Guell and Sagrada Familia) and Prague, and Berlin is mostly cool (though Munich is a bigger party). I heard great things about Budapest from a friend who lived there for six months. Amsterdam is kind of meh IMO and not really worth it unless you want to get high. I honestly don't think you need more than a couple days in each city, especially if you think it will give you another stop or two. If you had Paris in there, I might think otherwise. It's been a long time since I went, so I wish I could help more with the train details. Have fun.