I winterize and park it next to my garage (outside). It's wise to check that the caulking etc. is all up to snuff before winter. If you have vent covers over the roof vents, leave a couple vents open a bit for air circulation.
If there's electricity available, you can leave the batteries on some sort of a maintenance charger (or if you have solar let it take care of that). If not, charge the batteries fully and then disconnect them entirely and they'll be okay for the winter unless they were already at the end of their life.
