You don't need to limit yourself to the Dazhong btw. In fact, since you're not leaving until 5p the next day, you'll have ample opportunity to have fun.

I think this is the current airport bus schedule (basically, most of the numbered lines run until 11p and then there is a night bus that makes many stops):

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After all these years, I still maintain that #2 is the most useful/efficient for most people who want to go into Shanghai.