Groover the Colorado/Canyon is available in normal full length wheelbase. The narrower wheelbase is not a concern due to fighting a high COG but rather the high flat side wall of a TT. You tube has plenty of videos showing a TT and truck being blown over by wind and or flipped over from out of control oscillating sway. A narrower wheelbase has less ability to resist this. But agreed with proper hitch and weight distribution as seen on the axle weights of a CAT scale slip the diesel Colorado would do the job just perhaps with a little less roll over margin.
Travelnuts Good gawd you must have been a patient man to tow a 30'TT or an 8,500lb boat with a 130 HP 240 TQ diesel. Buddy had one of them 6.2 1500s back in the day. With a hot wired fuel pump and turned up injectors as he described it was way more enjoyable to drive.
D1H If you don't already have the diesel Colorado consider the now available for order Silverado 1500 3.0 diesel. 277 HP 460 TQ longer wider wheelbase for a stabler towing platform and as of yet undeclared mileage but certainly dramatically better the 5.3 and a better tow when you do hit the mountains. Mileage should be similar to the 2.8 diesel and who would not rater have an I6 compared to an I4 for towing.