Talked to a Colorado gasser v-6 owner that was towing

Not Diesel related but a little insight on towing with this vehicle footprint.
About a month ago we stopped by a Camping World Store.
We met a couple in a 2017 Colorado Non Diesel crew cab short bed basically same truck as our's but a V-6 Gasser.
They were towing a 28+' or so foot full sized camper with two slide outs. A newer Coachman Apex
They had a sway bar and leveler installed. The rig weighed 5,300 + dry.
I was surprised they were pulling it. Looked like way more trailer than the truck should be pulling. I asked how it handled and pulled etc.
They said it pulled it very well, almost as well as their previous truck a 1500 Chevy c/c short bed 5.3.
Not quite as powerful but really felt safe towing with it and pleased.
I would have thought it to be too much trailer for one of these trucks. They said they were avid campers and towed for years and were very pleased with it's performance. It didn't sway but they definitely knew the trailer was back there.
I asked about pulling a serious grade and they said it shifted down and was working at a higher RPM but got up the hills pretty much at the posted speed limit's.
Trans temp climbed on a hot day to over 210 degrees F but wasn't an issue. They had an 8 speed auto. The diesel uses the six speed auto.
MPG was around 10 or less towing that rig
They had add on strap type towing mirrors, and said it is a must for that rig.
If I get a chance to pull something like that with our's I will.
I don't want to go over the GVW ratings though.
I'm sure they were toward the top of their towing limits when loaded .
The 2017 Colorado/ GMC Canyon Crew Cab short Bed V-6 gas truck is rated to tow 7,000 lbs. in tow haul mode
The Diesel version is rated to tow 7,700 lbs while in tow haul mode.
I would have thought that a camper over 24' would wag the dog so to speak on a short bed truck like these, but they say wasn't a problem.. I will have to see for my self.

Interesting story.

This past August I drove a Ford Budget rental truck with a heavily loaded 16' box and while towing a Chevy Malibu on a car dolly from Montana to AZ.

We suspect that truck had a 5.3L gas V-8. With the load and while driven at 60-65 it delivered 10-11 mpg for the 1300 miles. It roared on the hills, struggled in headwinds, was slow to pass the few slower vehicles we encountered... and I really missed my 2500HD Duramax. Mileage wouldn't have been that much better, but the trip would have been more enjoyable.

So... if someone only tows occasionally, a gasser might make sense. They'll get the job done. For those who tow a lot more often - a diesel might make more sense.