Drive them all and see which is the most comfortable. I don't know if Ford ever changed it but the first Expeditions had a suspension that made for a lot of truck movement when towing. You will get better fuel economy with the Tahoe or the Durango.
I would want to be sure the used SUV came with the factory tow package and had 4.10 gears. Both are important for towing and will limit your selection. You can use the VIN to look up the specs for the SUV when it left the factory to verify this information.
