Still seems too high.Checking back in - realized I crunched some numbers wrong. Trailer weighed less than I thought. I was pulling about 3,750 lbs (enclosed trailer + gear inside)
I did still average 17.1 mpg there and back staying at a pretty consistant 70-75 mph.
Pulled about 5000 lbs of sound/PA equipment thru the mountains of Tennessee (Nashville to Atlanta). Couldn't even feel the trailer, honestly. I know 5k isn't really anything, but i could sure feel it when braking in my V10 excursion, so I'm very happy with the XD to say the least. Oh yeah.. i also doubled the excursions gas mileage while towing too.. averaged 17.1 MPG @ around 75 MPH there and back!