Hi, I need to travel from Shanghai to Yancheng in coming October.

As the two cities are not that far between, no flight is available. Train also doesn't connect between, so the long-distance bus is the best choice.

At the local General Long-distance Bus Station, many buses are scheduled. The first bus leaves at 06:50 and it takes about 4h to Yancheng. So you will arrive right around 11:00.