RFD and DFW are too far ground ops to the North East. KLCK can be trucked to the majority of the east within 2 days and a couple hours ground from SDF.
FDX uses AFW as a hub. Correct DFW is tight. Last Thursday afternoon I think every position on the ramp had equipment parked in it. There is room, not much to expand the ramp to the north at DFW.