Half of a 16-mile loop on mostly quiet roads around High Bridge + Califon in Hunterdon county - (also an 11-mile version). The other half is on the Columbia Trail (a dirt/gravel rail trail, very gentle). Much is near the South Branch of the Raritan River, including riding thru Ken Lockwood Gorge, perhaps the prettiest river section in New Jersey. For more details see www.roberts-1.com/b/x/nj - routeID [njwcrtr]. For the Columbia Trail, search on Bikely for [njwcolt]. One hill climb at northeast end of roads, which is avoidable. Map points were not tested for GPS navigation, but they seem to basically track the points I captured on my GPS that day. Not checked by me since 2009.by NJwandr