Are you aware of any resource where I can obtain comparable information about municipal roads for other municipalities in NY?
The best source for data on the number of miles a municipality maintains can be found on the CHIPs link provided by the New York State Department of Transportation. There is
also the NYSDOT Data Traffic Viewer
which can give counts for some roads. https://gis3.dot.ny.gov/html5viewer/?viewer=tdv.
NYSDOT Data Traffic Viewer