Sadly, it's time to close up the TT for the year. I'm planning to leave it parked beside of the garage, which will help shield it from the winter winds. When not used in the summer, I keep it plugged ...
Most people with the capability do stay plugged in all winter. Keeping the batteries charged will prevent freezing damage and will allow you to run stuff (furnace etc) over the winter to keep things limbered up. I think you should shut the fridge off though, open it up and let it air out.
If you unplug, pull the batteries and put them on a shelf in the garage. If you want you can put a battery minder on it, or just charge it up in the spring.