It's funny that I see a lot of people saying this, as if they think the F-150 just lugs along at low RPM when towing up a steep hill?
Uh, yeah, that'd be a no, for sure. The engine screams at ~ 5000 RPM when topping an 11,000 pass, just like the Suburban did.
The difference is that in the Suburban I was in 1st gear and going at most 25 mph. In the F-150 I'm in 3rd gear and going 55+. But it still revs very high and fuel consumption is terrible, in the single digit range.
In fact, I get excited if I'm able to get 11 MPG towing. It usually only happens when I'm doing most of my travel on relatively flat roads. In the mountains, 7 - 10 is more where I see my MPG at. And that's burning 91 octane premium (the highest you can get here in Colorado.)