I did a 20 hr "turnaround" as part of my 747 farewell flight using miles for seat 1K. I used TWOV so wound up exiting via NRT.

I used that time to go to Shanghai Disneyland. Took a taxi direct from airport for around $20 USD and 20 minutes. Bought a discounted evening ticket and rode Tron and saw firework show and stayed at Toy Story Hotel and then bought regular ticket the next morning. Hit the main rides then took subway into Pudong and went to the new Shanghai Tower for some great views of the city.

Headed back to airport via Maglev to get on my 4PM flight to NRT. Gave myself a couple hours just in case for possible slow processing but blew threw PVG security and immigration pretty quickly (less than 50 minutes from entrance at Maglev station to clearing security).

A pretty busy but fun filled weekend trip.