When you get off your train at Shanghai Rail Station on Oct 17, buy the ticket to Hangzhou of 21 directly. You can choose bullet train and you need to spend 63 Chinese Yuan for a second class seat. There are many trains from Shanghai to Hangzhou, but remember to ask the staff if you need to go to the Shanghai South Railway Station or the Shanghai Railway Station. On Oct 22, from Hangzhou to Suzhou, I suggest you take the T7786/T7787 to Suzhou and one soft seat ticket will cost you 67 Chinese Yuan. From Suzhou to Shanghai, you can also take D train and there are many trains. It should be easy for you get one. From Suzhou to Shanghai, it only takes about half an hour and you need to spend 26 Chinese Yuan for a second class seat.