I would make sure to have at least an hour buffer, maybe a hour & 15mins.
You will need to take the bus to MK or the TTC.
If you take the bus to MK, then transfer to the monorail going to the Poly.
20min ride to MK from POP (farthest park from POP).
15min ride to Poly from MK. (it is the 3rd stop from MK)
That adds up to 35mins. Now add in the possible "wait" times for both the bus and the monorail (each could be 20mins = 40mins)
Grand total of ~75mins if you have to wait extended times for the transportations.
Hope that helps you out!!