We have a reservation for Pitt's Intramural Fields on Wednesdays from 6-9 for the rest of this month. The field is located behind the Cost Center/parking garage.
I think that you should be able to park in the Cost Center parking lot and exit the bottom floor of the parking garage to access the field. The driveway entrance is at 3529 Allequippa St. If you can't park in the garage, then I think there is another access around 473 Robinson Street Extension.