I may or may not be in Taiwan this holiday, will know by midweek. If I'm still in Shanghai, a short ride around the local area would be awesome. A few ideas on some good rides worth checking out

1. Chongming island and northern Jiangsu province loop. Never done this one yet, and it sounds awfully enticing. There are ferries that would shuttle between Baoshan district and Chongming island. From there, it's a much shorter ferry ride into northern Jiangsu province through what looks like nice rural scenery on the map, quite likely good wide and fast roads. To get back, maybe go through Nantong on the bridge or another ferry across the Yangzte River if bikes aren't allowed on the bridge.

2. Zhejiang mountain foothills around Hangzhou. Moganshan comes to mind, but I think it's worth avoiding during the holiday as it would over-run with Chinese tourists. Other areas have mountains around Hangzhou, would be worth exploring.

3. Zhejiang Islands. Ferries also run to the other islands in the archipelogo such as Putuoshan, Zhoushan, and so forth. The more famous ones would be overbooked with tourists, but there may be some alternatives. For example, a friend gave some rave reviews of a less-touristed island within Shanghai province jurisdiction. It wasn't Chongming but another island that is visible from flights going into Pudong airport on certain flight paths. Can't remember the name of that island off the top of my head.