To remind: there is no direct way between Hongqiao and Pudong. Shanghai Metro "Line 2" is secretly 2 lines, with a connection at Guanglan Road.
Since you have 1 connection anyway, you are better off getting off Metro Line 2 at Longyan Road and connecting to Transrapid there.
What do you think would be a reasonable time allowance from arrival at Hongqiao Railway Station through Line 2, connection at Longyan Road and Transrapid, to checkin at Pudong Airport?