This would be a good way to find out what cities are non-IS!
I do know that every place in NJ is serviced by an XL. The southern Jersey shore has the IS as well. DE has IS. Salisbury had a JR. I think they still might have one. Lee, MA might have an XL and i think Waterbury, VT has an Xl and Bennington , VT has a 4000. (Comcast!)