towing qx56

Looking at the following 3 vehicles: Suburban, QX56, and Armada. Need to tow a 5,500 lb (as it sits - not dry weight) travel trailer that is 28' long and 32' tongue to bumper. Passenger weight will be 500-600lbs and not a whole lot of gear - maybe 700lbs. Using a Tekonsha brake controller and...