I use stabil diesel, fill the tank, and live in the north.
Make sure you drive around for half an hour, with the genny running and under load, to get the stabil thru the whole system.
And then put her to bed and let her lay. Nothing to be gained by starting the main or genny engines during winter sleep time.
Treat your batteries good tho. If you cannot leave the rig plugged in all winter, pull the batteries, take em to a warm place, and hook up a trickle charger.