The Kings Canyon High Basin Route is new for 2015, and there is not yet a robust community of thru- or section-hikers who can share their experience with it. Until there is, I thought it would be helpful to discuss the KCHBR in the context of other long-distance trails and routes.
Sierra High Route (SHR)
Steve Roper’s line along the Sierra Crest from Road’s End to Twin Lakes was the most direct inspiration for the KCHBR. It’s no surprise, then, that the Sierra High Route is the closest comparison. Both are rugged, committing routes that require a high level of athleticism and backcountry skill, and are worthy objectives for those who seek a pinnacle backcountry experience. There are important distinctions between the two, however, and the experiences are absolutely not synonymous. Notably, there is little overlap in their routing; the proportions of on-trail/off-trail mileage differ; and the logistical complexities are not even.
John Muir Trail (JMT)
The John Muir Trail and KCHBR share 14 miles of trail, are blessed with the same High Sierra climate, and require about the same amount of time to complete (1-3 weeks depending on the individual). But otherwise they are very different trips. The KCHBR is predominantly off-trail, features far more vertical gain and loss per mile, has more and more dangerous natural hazards, sees an infinitesimal fraction of the foot traffic, offers no “community,” travels further distances between emergency help, and lacks supporting infrastructure like on-trail resupply points, established campsites, and bridges. A KCHBR thru-hike is not an obvious “next step” for ambitious JMT thru-hikers, but a section-hike might be perfect.
Other long trails
Points of differentiation between the JMT and KCHBR, above, will apply as well to most other long-distance trails in the Mountain West (e.g. Pacific Crest, Pacific Northwest, Colorado, Continental Divide, etc.), though generally the High Sierra is drier and higher. Long trails in the East (e.g. Appalachian, North Country) are barely comparable, and an introductory experience to the High Sierra — perhaps using a KCHBR section-hike — would probably be prudent.