I'm closing in on two years of ownership of a 2015 F150 Crew Cab short bed 4WD with the 2.7 liter twin turbo V-6. I've put 30,000 miles on it since purchasing it used with 72,000. While I have not driven it with a pop-up camper, I have driven it about three thousand miles towing a pop-up camper which weighs in at around 2,750 lbs wet.
The "little sewing machine" engine is simply amazing. It does NOT require high revs to produce torque. The high point of its torque curve is 2,750 rpm. At 70 mph in 6th gear (a 0.69/1.00 overdrive) it turns a shade under 2,000 rpm so is well within the sweet spot of its torque curve. Empty, it never downshifts out of 6th on moderate hills at 70 mph and when towing it normally downshifts to 5th (but I can lock it into 6th and feather the throttle and just sacrifice a bit of speed towards the tops of the hills, which I normally do). Mileage is 20.0 to 23.0 mpg driving moderately and 19.0-20.5 at higher speed (72-77 mph). I don't tow at over 68-70 mph and the mileage is consistently 14.75 to 16.50 towing. All of my towing has been in the summer months with the A/C cranked up.
When I bought it I kept my old F350 diesel as a family backup and to tow with. On a whim, after getting a feel for how torque-y it is, I towed the camper to the Foothills of the Blue Ridge Mountains here in NC. It did so well then and since that I am strongly considering using it to tow the camper to Montana in August for what will be a 6,000 mile round trip.
And I'll be quick to add my son bought a new 2018 F150, identical cab/bed, 4WD, with the 5.0 and the 10 speed automatic. He's a leadfoot and the 5.0 sound gets good to him, but he reports empty Interstate mileage nearly equal to mine when, and if, he keeps his foot out of it.
As far as I'm concerned, you can't go wrong with the little V6 or the 5.0. And FWIW, mine takes off like a scalded cat when I choose to nail the throttle. Proof positive of the adage "you buy horsepower but you drive torque".
Foy