I find that our counties in New England really aren't that easily classified, so I decided to try classifying all the towns in Hillsborough County, rather than trying to classify all of New Hampshire's counties.
Urban: Manchester, Nashua
Suburban: Pelham, Hudson, Bedford
Exurban: Goffstown, New Boston, Litchfield, Merrimack, Hollis
Small City/Town: Amherst, Milford, Peterborough
Rural: Windsor, Hillsborough, Antrim, Deering, Weare, Francestown, Bennington, Greenfield, Hancock, Sharon, Temple, Wilton, Lyndeborough, Mount Vernon, Brookline, Mason, Grenville, New Ipswich
I also tried to do Chittenden County, Vermont, but this is a much more back of the napkin stab at it
Urban: Burlington, Winooski
Suburban: Essex, South Burlington, Colchester
Exurban: Williston
Small City/Town: Shelburne
Rural: Milton, Westford, Underhill, Jericho, Bolton, Richmond, Huntington, St. George, Hinesburg, Charlotte, Buels Gore
I like this. Let me try Franklin County, Massachusetts.
Small town: Greenfield, Montague, Orange
Even smaller town/"exurban": Bernardston, Buckland, Deerfield, Erving, Northfield, Shelburne, Sunderland
Rural: Ashfield, Charlemont, Colrain, Conway, Gill, Hawley, Heath, Leverett, Leyden, Monroe, New Salem, Rowe, Shutesbury, Warwick, Wendell, Whately
I was initially going to have a separate category for REALLY rural towns that don't even have a town center to speak of, but it's pretty hard to make an accurate distinction there. Also all of these towns contain a lot of rural areas; I put them in the most "urban" category they could plausibly fit into. Erving would have been in the "Rural" category if it wasn't for the bit of Millers Falls spilling over into it.
