We live in northern Wisconsin and our trailer sits outside in the winter > We wash and wax the exterior in the Fall
then cover the trailer . We also brace the roof for snow load and place the trailer up on blocks to get the weight
off the axle
and the tires
off the ground . We have Maxx Air window vents so we can leave the windows
cracked open for ventilation . We remove the cushions , anything that will be damaged by freezing , food items, bedding and leave the cabinet doors open.
The real solution to your question is to spend the winter as suggested in Florida . Getting the trailer ready to head South in the middle of winter is a real PITA . Last year when we left for our trip South it was 18 Deg F below zero.