Are you sure Greg Kelly cut across Baghdad from the east? He could have come up the road that runs from the southeast to the northwest on the east side of the Tigris, and then cut across that ring road over the Tigris and to the airport. But my understanding was that they were rolling due north on the road from the south, and once that road enters the city it gradually sweeps around to the west and straight into the airport on a very broad road.
The latter is my understanding of how Greg's unit came in.
Here's a good map:
http://www.lib.utexas.edu/maps/middle_east_and_asia/baghdad_inset_2003.jpg