Thanks for the suggestions.
I went to Beijing 2 weekends ago and loved it! Urban Planning museum was a surprise highlight and I had a great hike with clear air and fall colours with Beijing Hikers. I'm hoping for a shorter trip.
I was sick when I went to Nanjing, but I have to say I'm considering going back I loved it so much! I only saw a fraction of the sites around Sun Yat Sen's Mausoleum (including a couple of really quiet, lesser-seen museums) but could spend another day there easily.
I will look up Changzhou. I admit that I have never been there.
There are actually 2 HSR stations in Suzhou: the 'main' Suzhou station and Suzhou North (which is for trains to Beijing). The main station is MUCH nicer!
Dr. PITUK