Take Bus at Shanghai South Bus Station to look for buses to Jiashan. It reaches there no more than 2 hours later and then take city bus (about 3-5, I didn't remember clearly) or taxi (20RMB, negotiatation is needed), get to Xitang 20-30 minutes later. If going not in weekends and public holidays, you can get on a pedicab which will drive you directly to the town without paying the entrance fee (walk about 20 minutes). Stay one night and get to Xitang Bus Station for the bus to Jiaxing next morning. Jiaxing is 50 minutes away from Xitang, after arriving, find the bus to Zhouzhuang. Tongli is about20-30 minutes away from Zhouzhuang, where you can go just by rental car. Waters towns looks aimilar there. I just have been to Xitang, Zhouzhuang is crowded in holidays. Xitang has beautiful night scene and it was the latest discovered to exploited among those water towns around Shanghai. Tongli has three buses a day to Hangzhou, make sure the time in advance when you just get there. You can also make Xitang as your last town to visit. Jiashan has many buses a day to hangzhou.

Can no go to China early OCT because China National Day. They off a week for national day, very crowd.