Join Date: Feb 2001
Location: Rio Rancho, NM - USA
Programs: DL, UA, WN, Amtrak, Hyatt, Accor
Posts: 1,793
September is an excellent time to visit Europe, the summer crowds will be somewhat - repeat somewhat - thinned out. I agree with the Amsterdam, Paris, Rome suggestions made by Non-NonRev. Those cities and the modes of transportation recommended would be good choices.
For Paris, definitely learn a few words of French. Especially "Good morning sir/madame," "Good afternoon sir/madame," "Do you speak English," and "I'm sorry, I don't speak French."
Do visit the museums as suggested, you will be staggered at the beautiful art and sculpture everywhere.