2012 Yukon XL Towing 30Ft

That trailer is so much longer than the SUV I would not do it. It's usually called the tail wagging the dog situation. When a truck passes or there is a wind gust that trailer will be shoving the vehicle all over the road. But I'm sure some people will tell you to go ahead.

With either of those long wheelbase Yukons you will be fine. They're pretty close to a 20 foot long vehicle, no?
Get a good WDH with sway control and head out.

With the aforementioned "truck passing" you here is what I did when I was towing with my Suburban/30 foot travel trailer:

-as the rig approaches move over slightly to the shoulder, which increases the gap between the two of you.
-as the front of the rig reaches the space between your Yukon and the trailer is when you will notice your set-up getting a slight "pull" towards the rig. Slightly steer away from it until you can feel the "pull" subside.
-the rig will carry on it's merry way and you can center yourself back in your lane and start looking for the next upcoming rig.

This worked everytime for me.
Don't be fooled into thinking "you'll never feel anything with a good hitch". You will feel the "pull" regardless. You just want to alleviate it's affects on your set up.

Happy trails.

I'm sorry but I have a hard time believing that a 32'+ TT has a dry hitch weight of 362lbs.
The Denali will have a lower payload capacity because of all the fancy bling.

“Payload Capacity,796 lbs.” No, it’s 1,796.

Weight wise you may be okay. Length is too long...tail wagging dog.

I had a 2011 Yukon Denali XL that I used to tow a 7000 pound boat. My Yukon had a payload of 14xx pounds.

My biggest problem, and the reason that I sold the Yukon, was that when I was in the mountains my engine and transmission temps would get above 250*. I thought it was just asking for trouble.

https://www.rvusa.com/rv-guide/2008-r-vision-trail-sport-travel-trailer-floorplan-ts29bhss-tr695

This is where I got my information on the trailer

Well that is a long trailer but I think you should be able to tow it. I mean, this is a Suburban we're talking about. People keep wanting you to have a longer wheelbase. You can only get just so much longer. That's pretty much the same wheelbase as a crew cab short bed truck. The only thing longer is a crew cab long bed.

With good sway control and LT tires you will be fine as long as your weights are correct. The unloaded weight of that length of trailer seems low to me. The wheelbase is as long as most trucks.

Which Suburban ?

Half ton or 3/4 ton ?

Both use the exact same body...everything below the body are different

Bigger frame, bigger power train, bigger suspension, etc...why a3/4 ton sits higher than the half ton

Since the OP mentioned the Denali Suburban...think only looking at half tons

The 2012 and 2013 are the same chassis and almost the same vehicle, except I'd take the 400hp 6.2 all day long and twice on Sunday if the regular Yukon has the 5.3.
Either are capable and sized right for that weight.
Length is just a function of how good of a driver you are. 32' long trailer is a snap if you're comfortable towing and backing or a bit of a challenge negotiating some places if you're not.

You're totally within the limits of both of those vehicles though if you're really only 6klbs loaded.