Using the Gmap Pedometer, I measured a few of the longest aisles in the various lots.
AK the longest aisle I could find was about 700 feet long. (This actually held exactly true in a few rows in a few different sections of the lot, which leads me to believe the layout of the access lanes and tram lane were built specifically so that was the longest possible length)
At the MK/TTC lot, the longest aisle that would require the tram ride is about 750 feet long. I found one aisle about 780 feet, but from that point it was about the same distance to walk to the TTC as it was to the nearest tram lane.
At the Studios I found a couple aisles close to 900 feet, some in the 800 foot range, though most were in the 675-750 foot range.
Epcot was the clear winner (loser?), where the longest aisle was 910 feet. (And most in that section were the same length, so unlike the other lots where only a few aisles are the "loser" aisles with the long max length, that section of the Epcot lot everyone is an equal loser)
-Rob