I'm actually going to second the idea of staying at pvg. Because of the arrival time, you can basically guarantee you will be out later than the metro or maglev is operating (from what I found they are only allowing entrance past 10:30 at near-expo stations). So you can guarantee yourself a taxi ride or two during your evening, fine they are a lot cheaper than the US. You might as well make it one big taxi trip at the end of the night, than a lot of little ones throughout the evening trying to get between hotels and metro stations and the maglev station etc, and then again in the moring too, getting back to the maglev.

Metro is very honestly faster for most trips I took, than a taxi, so using it not only saves money but time, if you understand how to use it efficiently. So I like the idea using public trans as much as possible until 10:30 and then that lessens your overall exposure to taxi trips. Which means you would either want to stay at the city end of the maglev line, or the airport, so as much as your onward travel that evening, is earlier and on the metro, and not spend on further travel to a hotel.

The are a couple of hotels around the maglev terminus but not many, but what there is, is a major metro tranfer station with a line into the downtown and a line towards the SW and expo. So I agree the best idea for time purposes would be to get everything checked in and changed before or after the maglev ride, and then you'de just be ready to go, and have 4-5 hours to ride the metro before you have to start taking cabs, and non-rush hours too. For example getting to peoples square from the maglev, will be much much faster in the metro than by taxi.

The only downside is you will not see anything in the morning if you stay at the airport. So maybe you should decide how late you would tend to stay out.