Peter - It sounds like synthetics are good in a large temp range for extended cold temps so no issue there. Seems putting $70 worth of new oil in and if you want replacing in the spring is a not an expensive investment. If you do need to drive it for any reason at least it won't be empty of oil.
When I lived in the Lake Placid NY area I would see both used and new cars sit for 6 months on dealer lots and they would only get driven from one end of the lot to the other. Doesn't mean it is OK, but it has been this way for years.
I have extra room in my garage in NC if you want to store it here
...I'll treat it like one of the family
