That is very interesting for sure. It is for sure still possible to hike it, a lot of routes out west are very similar in nature. In the Whites people are generally used to trails, so routes like this seem forboding, but depending on your skill set, it could prove to be a worthy adventure. As the guide stated though, un-maintained routes of this nature, carry some issues not associated with maintained trails, ie. route finding, loose rock and technical difficulty of an unknown rating. It could be a tough hike, or it could be class 3 or 4, any route of this nature would have to be evaluated as you climb it, and knowing your skill on varied terrain would determine if you should climb the whole route or retreat in the face of unfavorable conditions for yourself. Having done all the routes in King Ravine myself and just having to guess, I would say it would be similar in nature to the Great gully route.