We're staying 2 extra nights in Shanghai. For one of the days we're taking a private tour out to the Shanghai water towns.
There are several options, but we booked a tour with Miki,
https://www.tripadvisor.com/Attraction_Review-g308272-d2522351-Reviews-Miki_Tours-Shanghai.html
Seeing a water town was something I really wanted to do on my 2014 visit, but didn't have a change.
I would strongly recommend spending just a little bit of time at night and walk along the Bund promenade. That gives you the awesome view over the river to Pudong. Certainly that and Hong Kong are 2 of the most spectacular skylines to see at night anywhere. Shanghai was my favorite skyline. Absolutely spectacular.