Google Maps now shows the difference in trail surface between the section of the Pumpkinvine that has a limestone surface and the sections that are asphalt. See https://www.google.com/maps/@41.6026551,-85.7926863,2805m/data=!3m1!1e3!5m1!1e3?hl=en  If you activate the bicycle friendly feature of Google Maps it shows the asphalt section with a green line and the limestone section with a brown line. The Key calls the latter “Dirt/unpaved trails.”