I briefly towed my trailer in sig with a 03 Navigator that is basically an Expedition with the 4 valve (300hp) engine. I lightened the tongue weight by moving propane tanks into the rear of trailer and removed unnecessary junk esp stuff stored up front under bed. That truck had auto adjusting air suspension so had to hook up WD with switch off then turn it on and it drove fine to me for the short trips I took. Wouldn't classify it as ideal setup though but I felt safe with it operating on short trips on flat land. I also have towed it with the recommended Excursion both the V10 and 6.0L and find them much more capable but slightly limited with soft rear suspension but definitely more stout than the Expedition/Navis. I also had Suburbans 2500 (can get cheaper) albeit the older body style with 7.4L which also towed it fine.
