Yup, if you can move South until you hit an area where little furnace use is in the cards, it's an easy and beneficial solution.
It sounds like you might enjoy a larger trailer. That may or may not fit your plans. There are always ways to increase storage or alternative ways of storing things. Right now, I have a 15" spare tire in my shower enclosure. I don't plan on any Winter trips and I do plan to install the spare in different exterior location.
Is the storage area under the seats being used, right now?