The other name for this approach is the Harwood Trail. Though the hike matches the gain of the Ski Hut route, it's about a mile shorter. But the section from where the trail forks off the Ski Hut Trail to where it meets up with the Devil's Backbone Trail climbs 2500' in one mile!
Its steepness is why, though shorter, this route is really no faster. It is, however, one of the prettiest ways up Baldy. Additional note: the beginning of this trail is much more pronounced and obvious than it used to be.
I've descended Register Ridge twice, and each time I made the same mistake: I left the Devil's Backbone trail too early and wound up traversing steep, loose, and generally unpleasant (even in retrospect) terrain. The first time I never made it all the way over to the ridge and simply descended a miserable gully until I landed in a dustheap on the Ski Hut trail. The second time I traversed a surprisingly (and again, unpleasantly) long way until finally intersecting Register Ridge. I couldn't believe how far over it actually was.
Since I have botched the descent twice (making the same exact mistake each time), I do not know the best place to leave the Devil's Backbone trail. Instead, I would recommend being very careful about not leaving the trail until you are actually on Register Ridge proper.
I enjoy climbing this route, but have never had the desire to descend it -- a bit too steep. Besides, there are several better ways back to Manker: the Ski Hut Trail, Devil's Backbone or just scree ski down the Bowl.
I enjoy descending this route. The scenery is great, there are no crowds on the weekend, and it is certainly not boring coming down. It also helps work out some different muscles. In terms of finding the route down, the trail is now visible when there is no snow. If you are looking up the most direct little jaunt to Mount Harwood from Devil’s Backbone you will notice it has no vegetation and then, a little farther down Devil’s Backbone going away from Baldy vegetation starts. Turn a corner below the vegetation and the trail will be off to the right, there being a nice sort of sitting rock to the left of the trail at the turn off point.
I always enjoy this route, both on ascent and decent. One of my favorites for mountaineering conditioning. It's definitely not a route for the casual hiker though. It's also shocking how dead quiet it is even on the busy weekends. I love it. Most recently decided to take on the Class 3 crag instead of bypassing it. A whole lot of fun even if only about 15-20 ft, was the highlight of the entire trip! I wish there was more Class 3 on this route, in fact. Though I've learned of some other sustain Class 3 climbs in the Baldy vicinity that I may spend my time.
As of Sept 2014:
The bottom 1/3 of this route is 50 degree (momentary up to 60 degrees) and in pretty rotten condition right now, lot of foot slippage even with good-traction boots and careful footwork, requires occasion hands and climbing over a few obstacles - I'd say this section is Class 2-ish right now. This section can feel demoralizing the first time on this route, but after the ridge levels off to more solid ground, the additional 2/3 of the way are strenuous and rolling Class 1 but not QUITE so precarious.
Register Ridge on descent... totally different story! But fun. And challenging both mentally and physically. Poles highly suggested. It's fun, but expect to take slow careful steps or find yourself accidentally scree skiing. Junction to it from Devils' Backbone is easy to spot on descent right now if you know to look for a use trail on the right - not sure how it compares to the reports from earlier years.
A tip I learned from someone outside of SP for route-finding issues, hopefully will help those who have had trouble on the route: On ascent, when in doubt about the trail, stay just barely to the left of the ridge crest - on descent, the opposite (as in, stay the right since it's all in reverse now).