The dashed blue lines on this map are user trails based on GPS data collected by NPS staff.
The NPS is hosting this trail data on a GIS server. Click any trail to see a popup with all the attribute data the GIS server has for the thing that you clicked.
http://www.mappingsupport.com/p/gmap4.p ... ton_np.txt
Click the "About this map" link in the upper left corner to find out how to turn other GIS layers on/off and do more cool stuff with the map.
Joseph, the Gmap4 guy