My take: Upstate New York refers to the part of New York State (outside Long Island) that does not maintain close ties (in
terms of commutes, etc.) with NYC ... The NY 17 corridor presents a difficulty. Many New Yorkers spend weekends in Sullivan County (moreso in the past than today), but otherwise the area isn't really connected to NYC. I guess I'd call it upstate-with-a-footnote.
Litchfield County, Connecticut presents a similar situation. If it were in New York State, I suppose it would be another example of Upstate-with-a-footnote.