does the Yukon have the factory tow package, because you mention getting a trans cooler.
if it has the tow package, it comes with the trans cooler.
and living in Cali, you're not going to be happy pulling over the Sierras, since you'll easily be at the Yukon's limits.
the Windjammer only has a CCC of 1600lbs., with about 400lbs. of that counting towards the "options".
so, you'll easily be at the Windjammer's GVWR when loaded for camping.
same goes for the Laredo.
IMHO, i would never risk my family pulling a 36' TT with a 1/2 SUV.
and either trailer will easily weigh around 8000lbs., being pulled by a 1/2 ton with a 5.3 engine.:E
the GMC Trailering Guide shows only 8100lbs. for the 5.3 Yukon and that's with only a 150lb. driver in it. anything else it it, lowers the 8100 number by its weight.
you need to really scale back what you're looking for. find an ultralight TT under 30' long.