Tire pressure before going south

WAYYY over thinking a simple answer to OP's question. I'm OCD when it comes to checking tire pressures on all my vehicles as well as our 5er., but as stated earlier, just check the tire pressure the next morning.. You'll use the recommended tire pressure for your tow vehicle, just like you'll check tire pressure on your 5er and go by recommended psi for those tires as well, OR air to psi that you normally would when checking the tires COLD air pressure, i.e., after TV and 5er have sit over night. I've left one place where temps were in single digits..aired tires on truck and 5er to recommended cold air pressure, traveled to a location where temps got into the 50's and adjusted my truck accordingly the next morning and re-checked air pressure in the the 5er's tires the morning we left... It's really simple. Never had an issue with tires running over inflated, under inflated, worn out early, etc..

The tire manufacturer has figured all this in when Engineering and manufacturing the tires, and have set max sidewall cold air pressure accordingly.