I don't drive a ford, but I drive a Dodge Durango Hemi. I have a Bullet 281 BHS (ie 32 feet). Tow capacity on the Durango is 7500ish. I have added Bilsteins for stability and I have a serious WDH, and upgraded brakes and a good controller. Weight-wise, I have no prob with the bullet, with is 5100 lbs. And I have been everywhere in Colorado.
But I have been towing for a while. And I know how to downshift in mountains. I talked with one gentleman with a small popup with a 250 who nearly drove himself off the tetons because he didn't know about first and second gear and tried to brake his way all the way down the mountain :E.
Alot has to do with 1) your personal experience in towing. 2) What have you done with your equipment. 3) How careful are you with loading. My old pop up (coleman niagra) was a bear if you did not load the front correctly because it was very tail heavy.