Ah, thanks guys. This is really useful. So I think I may modify jiejie's amazing itinerary a bit and start by going from Beijing to Pingyao instead of Shanghai.

So I'm thinking:
Beijing-Pingyao-Xi'an-Chengdu-Lijiang-Yangshuo-Shanghai-Suzhou-Hong Kong

I've cut Kunming--is there anything particular I want to see/do there? I found some cooking classes along the way so I think I'm pretty set for stuff to do!

I'm going to go attempt to get my train ticket to Pingyao today. I can only imagine that it will be interesting.