I wouldn't get worked up on the HP/TQ numbers. Sure a NA engine loses 3% of HP every 1000' in elevation. But just think 5, 10, 15 years ago, 3/4 and 1 ton gas trucks had less than 250HP. Same with diesel. Now a 5.3L from GM pus out 350HP and a 5.7L from Ram puts out 390HP.
A EcoBoost F-150 has the HP and TQ to pull a heavy camper. Stopping and controlling it is another story.
The 6.2L gasser in the F-250 pulled the camper just fine up the Ute Pass. I was going 40-45MPH up with no issues. RPMs stayed around 3-4K, so it was a little loud. But nothing wrong with having the engine work a bit. Just kept an eye on the tranny temp gauge.
I need to get the rear suspension beefed up a bit. Sanked the rear end 1" down even with an equalizer. The tech who installed the hitch said he put the same trailer on a new Ram 1500 and the rear end went way down.
I need to spend some time with the equalizer to make sure it's setup properly, don't trust an RV tech even if he's been installing them for 15 years.
If buying a new truck, definitely go a 3/4. Look better and a lot more capability.
2016 Sunset Trail 270BH
2011 F-250 CCSB FX4 6.2