I reported the Ecoboost mileage with my old trailer earlier in this thread as ~12.5 mpgUS.
With the new trailer I've got 9.8 mpgUS from the B.C. interior to Ontario and down to Florida. As usual, the worst mileage was on the prairies against headwinds. That's about a 27% reduction in mileage relative to the old, but I'm expecting it to improve a bit as we drive around the flats of Florida.
The frontal area of the new trailer is 64 sqft, about 19% greater than the old's 54 sqft (and exceeding Ford's recommended max of 60 sqft).
The total rig weight with the new trailer has increased by 32%.
My max speed is around 62 mph (100km/h).