You are overthinking this by a lot. You have another problem staring you in the face, yet you don't even realize it.
Your GVWR is 1313 lbs more than the curb weight of that Yukon XL. Your estimated tongue weight is 750 lbs, leaving you 563 lbs. If you put 30 gallons in the fuel tank, you are now down another 240 lbs, leaving only 323 lbs for all passengers and gear.
Since you drive a Yukon XL and bought a bunkhouse trailer, I am assuming there are numerous kids involved? If you have 2 adults averaging 180 lbs in the front seats, that leaves -37 lbs
and we haven't even gotten into kids, snacks, their entertainment, luggage, etc.
You need a 3/4 ton SUV for this.
