Too late to help you, but in case others read this thread with a simliar issue: the other option would be to catch the Septa train at the E terminal and simply ride it to the A terminal. This would take less than 5 minutes and would be free since they don't collect tickets until the train leaves the airport.
The train runs every 30 minutes, so depending on the timing, may or may not be quicker than walking, but will certainly save you having to sweat it out on the sidewalk.