Here are my thoughts on why we went with the D Max Colorado, it might be helpful since it touches on some of the points made in this thread, especially in regards to towing.
So as I mentioned earlier in this thread we just brought home a new Duramax Colorado long bed. We had a good sized number of other vehicles we were interested in as well. They included the 4x4 Sprinter crew, the new Raptor, the new Tacoma TRD Offroad, the Ram Ecodiesel, and the standard domestic half tons. The primary need was to get my wife a new daily driver that could be used for road trips, camping, hauling firewood, hauling mountainbikes and gear for our activities, and safely shutting our youg ones. She was in a perfectly nice 2004 Outback that has had zero issues. The concern was I was paranoid of her driving our two little guys around in on UP roads in the UP winter often in deep snow and where 75% of the other vehicles on the road are full size trucks. We also have a 2004 Suburban 3/4 ton which I love but essentially gave us two vehicles of the same age and mileage. So, rather than have to replace two vehicles possibly around the same time 5+ years from now we decided we should replace one now. My wife has wanted a pickup, specifically a Tacoma for ages. We both agreed our dream rig would be a Sprinter 4wd crew but that and the Raptor were more than we wanted to blow on a new vehicle, so we eliminated them. We also have our 23 foot Freedom Express Ultralight camper that weighs in at 4,200lbs dry and it would be nice to have a backup way to tow that. The primary tow rig is the Burb, and it does it with no drama, and competently. It has 4.10's, the 6.0 and a tow rating of 10,000lbs. We dont have to use weight distribution or anything on the truck and it has zero sway, even with the trailers wide, and tall profile.
Being a daily drive it had to be comfortable, it had to fit our family of four with two kiddo's in child seats and have the ability to do a four wheel camper or something like a flippac down the road for traveling light trips without the camper. So it needed reasonable payload which suprisingly, many half tons don't have much of. The Ram Ecodiesel is rated for 900 pounds so after passengers you can basically bring a pack of mentos along. We wanted a good daily driver that was easy to drive, park, pull into our garage, that was under the radar.
Ok, so we looked at the Tacoma, obviously its tow ratings aren't as good as the Colorado but it has a huge aftermarket, more competent offroad stock for stock, and has good resale. It also was cheaper MSRP vs a Colorado with the Duramax. The Tacoma has too much of a knees up, low seat driving position for me and the view out is a bit compromised. Plus we both agreed that the styling was too much "Hey look at me" for our tastes. The bed in the Taco is pretty shallow too which doesn't make it as practical. Finally, after having had an FJ Cruiser for a spell and using it for overland trips, I feel the build quality of the newer Yotas doesn't live up to what it once was, thought they are still well built and a nice place to be.
The local dealer had two D max's on the lot so we went and test drove one and were super impressed by the ride, the drivetrain and the solidity of the structure. These things are put together well. Having the ability to get over 30mpg on the highway, which is better than her Outback was was pretty cool. Yeah, yeah, justifying the cost of the diesel by mileage, blah, blah... good point, but what that doesn't take into account is resale and I will bet heavily that down the road when we go to sell, assuming something unforeseen doesn't occur in the market, the resale cost of the diesel over the gas will more than pay for the initial cost.
I have said for 20 years now that if someone brought to the US a good, mid size truck or SUV that was diesel I would buy one (wasn't stoked on the Liberty though considered one). I remember in the early IH8MUD days and even prior when that comunity was on the old Specter Offroad forums we had email campaigns to ask Toyota to bring their diesels to the US. I have been a LONG time Toyota guy.... My first dream rig was a 60 series and I have had a couple of those, a first gen Tundra, and FJ Cruiser, and we still have our built 80 series that I have had for ages. But the fact that Chevy stepped up and brought this to our market, well, this is me putting my money where my mouth is. I was a supporter of the auto bail out and am proud to be doing a bit of driving local these days so that doesn't hurt. We also figured if we were going to use either the Tacoma or the Colorado for the type of stuff we use the Cruiser for, we would likely lift and equip them anyway which pretty much negates the plusses the Tacoma has anyway. All the traction mode stuff is great for rookie offroaders but I don't think is really necesarrry, obviously thats just my opinion though.
Price, the Tacoma TRD Offroad in the sexy quicksand color our local dealer had stickered at 36k. The long bed LT trim, fairly well loaded, long bed D max we bought stickered for 41k. They had 6k worth of incentives on it, PLUS we both get the GM family discount so we got our Colorado for 31k PLUS 0% for 5 years. I was blown away. I couldn't justify anything else with that as the cherry on top, but even for 40k we would have preferred it. Again, we ruled out full size due to daily driving, parking hassles and her not wanting to deal with that.
Ok, now specifically in regards to towing. Yes, the Colorado is smaller than a full size, lighter than a full size and some things with physics can't be avoided. There was reference to a TFL truck video earlier where they had sway in one test with a high profile trailer. They didn't have weight distribuition nor sway control. They also had the shortbox. The long box like we went with has a 140" wheel base vs our 3/4 Burb's 130. That should help stabilize things quite a bit. With our camper loaded for one of our mountain bike trip odysseys We are a smidge over 5,000lbs. Given the tow rating of 7,600, and the margin that leaves us, despite the high profile of the camper, I feel confident this thing will be great. I have towed with about every rig imaginable and done so for years, so I consider myself pretty well versed. With the addition of two little ones, I have become pretty damn risk averse so I take towing safety pretty seriously. With our weight distribution setup I am feeling pretty certain we will be all good. Yes, of course a 3/4 ton will pull better, no question, but I would rather pull my teeth out with a set of pliers than daily drive an F250/350, especially a diesel. The ultimate determination though will be after the snow melts here and I actually hook the thing up this spring and give it a run. We also are expecting 12-14mpg towing with it versus the Burb's 6-9mpg. Again, the Suburban is the go to puller, but if we can run the Colorado from time to time with the camper that is just money in the bank.
So to the orginal poster, pulling the smaller camper you are talking about should be a breeze and I would bet on that. As mentioned earlier, there are a bunch of accounts of folks on Colorado fans and some of the RV forums who have been using them for smaller sized campers and it seems positive. I think this is a case of the right size truck for the majority of the things you need.
GM build quality has been increasing exponentially but the drivetrains for the most part have always been solid. Our 2004 Burb is a beast and I have all the confidence in the world it will hit 300,000 with no tranny or major engine issues. The newer stuff though more complicated is much better put together. My worry is more along the lines of the integrated technologies on the cars 15+ years from now and what will happen when there are software issues in those technologies. That is the unknown that I worry about a bit. Not the really the drivetrain or durability.
Sorry for the long post!