There is an overnight boat from Hangzhou to Suzhou. Ticket costs 78, 88 and 98 Rmb for one person.
You need to buy ticket at WuLinMen station on HuanchengBeiLu. Close to Pizza Hut. Take bus K156 from Railway station and get down at WuLinMen. Boat leaves 530 PM everyday

Hangzhou transportation is well organized. No need to travel in taxis! There are Holiday buses (Y) which cover all the tourist spots and are frequent. Hangzhou attractions are well planned and can be covered in buses.

Generally its hard to get train tickets during festival season.
Check for other ways of getting train tickets from you chinese friends. Sometimes you get tickets by paying some extra amount. I dont know if this is reservation or some other thing.