Numbered "metrics" would be hard to come by, but number 1 is your own comfort level with the experience. Does it feel stable to you, does it have enough get up and go on the local hills. This is highly personal.
On one trip this is hard, but differing conditions are nice, wind, speed, trucks on your sweet spot at the rear and hills are all going to have their own effects you will eventually come across and if possible nice to know about upfront.
If you have an empty road give it a bit of a try back and forth to see how it would react if you suddenly had to avoid something. Nothing too severe, just see how it feels when pushed a bit. I typically run with higher tire pressure when pulling, up to the sidewall maximum, and that can make a surprising subjective difference depending on the type of tires you have on the SUV.
