I thought that Pan Gate and Ruiguang Pagoda was really good. Wonderful garden and lots of koi fish you can feed (a kiosk in the middle of the lake sells fish feed for ¥2). I also spent an afternoon walking around the canal. If you look on the map, there's essentially a square river/canal that surrounds the city center. There is a walking trail and parks all along it. Consider it in conjunction with the river cruise, perhaps.

Shantang street looks good too, but it was far too crowded when I went during a major Chinese holiday. Hopefully you'll have better luck!