I traded my 15 yr old Dodge 3/4 ton Diesel for a 2014 Expedition, the short wheelbase version, not the EL. It has the 5.4 V8 with the towing package. I specifically needed something that would be capable of towing our RV. It's statistics are:
Arctic Fox 25Y
30' long
about 7500lbs as I usually tow it (with empty water and holding tanks).
Tongue weight is about 750lbs

I have an Equilizer 4pt anti-sway load leveling hitch and had to adjust the ball height, hitch angle, and moved up to the 10,000 lb leveling bars since the ones that were on the truck didn't seem to have enough strength to transfer enought weight to the Expy.

We usually tow from Denver, about 6,000', to Summit County campgrounds. This is up I-70 over the mountains thru the
Eisenhower tunnel at 11,158' and down the other side into Frisco, CO at close to 9,000'.

The diesel truck usually towed the RV at 60-70 mph and slowed to about 55 at the steepest parts of the climb. It averaged about 12-14 mpg while towing this route. The Expy doesn't have the hp, torque, or wheelbase so I didn't expect to duplicate the truck's performance. What I found was the Expy would tow it at 50-60 mph and slowed down to about 45 on the steepest parts. It also got pushed around a little in crosswinds but I quickly got used to it and it wasn't a problem. Mileage was about 13 mpg over the route.

So, bottom line, it will tow a little slower but just as safely - in fact the 5.4L V8 coupled with the 6 speed transmission required far less braking going downhill than the diesel truck and gave a confident feeling of being more in control.

BTW, the difference in time to tow from my home to the campgrounds, about 75 miles, was less than 15 minutes. In return I have a quiet ride with a great sound system, with 10 years newer and 100,000 fewer miles. I'm definitely pleased with my new ride.

 

You sure about that 13 mpg while towing? My 07 is basically the same rig, runs and tows excellent, but gets about 8 or 9 at best towing my 24' enclosed car trailer empty on flattish highways.
16/17 highway not towing and 13 or so around town.

 

I guess I didn't make it clear. I towed from home to Heaton Bay campground over Loveland pass thru the tunnel about 80 miles 65 of it uphill then drove back home without the trailer but at 65-70mph. Then I filled up when I got home for a direct diesel vs Expy comparison.

I haven't had an opportunity to tow it on level ground for any distance yet. Without the trailer and driving 65-75 on relatively flat highway I've gotten about 19.1 mpg. Driving around in town and back and forth to work it gets about 14.8 mpg. The diesel truck got an all around average of around 17.5 over 160,000 miles.