If one walks behind the Baskin Robbins / Dunkin Donuts the ROW is easily walkable. A few old rails and ties are still strewn about, but nothing of any great interest.
If it weren't for one building occupying the ROW near Caldwell College, one could walk from Roseland Avenue in West Caldwell all the way to Great Notch on the ROW. The old bridge over the ROW on Bloomfield Avnue was filled in maybe fifteen years ago, so you'd have to walk across I suppose.
The latter half of the ROW (from just east of Bloomfield Avenue) is used commonly as a walking and biking trail. About a mile and a half is maintained as such by the towns. If you follow to the end, you come out on NJ Transit property (if you pay taxes, your property) just west of the horribly maintained Great Notch Station.