Just got my issue of Drive magazine and apparently October is winter car care month, or something close.
A couple things I have done in the past to prep for winter are:
Grease door hinges and straps
De-ice/grease door locks
Lower freezing point washer fluid
fully clean and wax paint
Make sure newish wiper blades are installed
As for folks who mothball their Subies for the winter, WTF did you buy a Subaru for in the first place?!