while not the Denali, we have been pulling our Terrain since it was new. Simple set up procedure as all you have to do is pull a fuse (#34 - I think), put the trans in neutral, and the ignition in the "on" position. There is a max 65mph requirement, but since we only tow at less than that, it's not a problem for us. I have gone over 65 many times (down hill, passing, etc), but typically stay at 62 or 63.
As for the fuse, I replaced mine with a switch so that it's just a simple matter to flip it and I'm good to go.
The car has been a perfect toad for us, just the right size, weight, and is comfortable, gets good mpg, and is very quiet. We now have about 80K miles on it with about 20K as a toad. Other than oil/filter change, all I've done is replace the battery and tires (both around 70K miles).....that's it, nothing else. I've noticed that the 2016 V6 comes with a 301hp engine...wow! That's a lot of hp for a 4000 lb car. Ours is the 4 cyl (185 hp) and suits us just fine.
We chose the Terrain over the CRV for several reason, and turned out to be an excellent choice.
Ron
Ron & Sandie
2013 Tiffin Phaeton 42LH Cummins ISL 400hp
Toad: 2011 GMC Terrain SLT2
Tow Bar: Sterling AT
Toad Brakes: Unified by U.S. Gear
TPMS: Pressure Pro
Member of: GS, FMCA, Allegro
RETIRED!! How sweet it is....