Find a flat parking lot or road. Measure ground to edge of fender well both front and rear wheels on one side. Hook up trailer and re-measure ground to fender well both front and rear wheels. This will give you an idea of what the added weight of the trailer tongue is doing to your truck. Get some feel to how it could be affecting your truck. Tire wear is also a concern if you have excessive weight on the rear of the truck.
I've got a 2011 F350 crewcab/full 4 door, short bed. I'm getting 18 to 23 mpg when NOT dragging the TT. Hooked up to TT I get 13 mpg, up hill and flat ground.
I just bought the AFE cold air intake box with programmer. Haven't had time to install yet. I have 60,000. No problems.
Couple annoying things about this truck is my oil change schedule is every 7,000. But the DEF tank runs low at 5,000. Also you 2011 owners, I was returning home thru Portland/Vancouver and estimated I had just enough fuel to get me into Longview to re-fuel. At 30+ miles to empty (and only 20 to go to fuel station) truck starts giving warnings and soon goes into limp mode. At 20+ miles to empty the truck shuts down and glides to the side of the road (only 2 miles to fuel station & exit in sight). Have to tow both truck and trailer (didn't know it was just low on fuel with 20+ miles to empty indicated). Turns out Ford has built in protection for the diesel engine to prevent it from running out of fuel and severely & expensively damaging the engine. Seemed to me Ford should spell that out clearly and loudly to prevent this from happening to new owners.