Lawman said:
Couple other places that are great spots, the Isle of Capri of the coast of Italy... all I was very happy with Rome, but you need at least 2 days to see everything.
Believe me I lived in Rome for 6 months and I still didn't see everything! Capri is awesome. I swam in the ocean in February. I will say though it is a very long train ride all the way down to Italy from the Neterlands. It's about 21 hours to Rome with a stop in Paris first and another hour to Naples. Rome being in the middle of the country will be about as far as you want to go if you can't fly. You can take ferrys to Sicily from Naples too.
You have to go to Switzerland. Especially if you ride motorcyles. The Autobahn goes through the mountains and has the most unbelievable turns and views.
Go to Haufbrau House in Munich for me and drink a beer!
If you can, fly to Istanbul, Turkey and/or Athens, Greece. I had a blast in those two cities. And of course Salzburg, Innsbruck (where the olympics were held), and Vienna, Austria are beautiful, as is the French Riviera. Go to Paris to say you where there but don't judge France on Parisians, hahaha, they aren't the same "species."
I must say I had the same agenda as you did when I was in Europe, although I was there for a lot longer, see everything. Stay in hostels, they are so cheap and I'm sure you're used to not having the best accommodations all the time. Pack light while traveling, as I'm sure you've had practice doing, but pack for EVERYTHING. I never had any firm plans and always ended up in the most unpredictable places. Pack for anything from walking for hours, to going to the Discotecha, to cathedrals (remember no shorts or bare shoulders allowed), to the beach, to bungi jumping, sky diving, or rock climbing or the fanciest restaurant in Paris or Capri. Although I probably had one major thing on you, I'm a "cute, American girl" with blond hair and blue eyes (something they don't see often, especially in Italy), everyone was nice and wanted to take me everywhere. I met people everywhere I went and got into exclusive discotechas and had the fanciest dinners bought and paid for. Remember anything can and probably will happen so be prepared and have a blast!