Last week I went for a walk around Nanxiang another one of these “ancient” water towns. It’s not really a separate town, just a few old streets in Shanghai’s Jiading suburb. You can reach there easily on line 11.
The best part is definitely Guyi garden which is the classical-style garden pictured above. I went on a weekday and it was pretty quiet. There’s also an extensive Buddhist temple which is free to get in. Definitely recommend this one over Qibao, but there’s much nicer old towns if you go to Suzhou or somewhere a bit further away from the city.