We've booked a hostel in the centre of Shanghai for three nights (Fri 1- Sun 3). We'll take the train -buying tickets on Monday as you can only buy them EXACTLY 10 days in advance apparently- which will take about 10 hours. Comfortable seats/sleepers methinks. It won't be the only occasion to visit Shanghai so the short trip's ok. Hostel's called Biktime, No150 Xianggang Road if you're interested...