From the bench above Black Lake, we hiked south to Frozen Lake and continued around the south side of the lake. At this point we headed due west "scampering" about boulders towards Stone Man Pass. In hindsight, we should've headed due west once we reached the bench above Black Lake, as the route we took ultimately led us to a highpoint near Stone Man Pass which prevented easy passage to the gully which must be climbed to reach Stone Man Pass.
Upon reaching the "impassable" highpoint near Stone Man Pass, we stopped and considered what we should do next. We thought about forcing the issue and making the route work, but ultimately we decided to drop a couple hundred feet and thereby take the easier route. I suppose the "impassable" route is climbable, but I think the right decision was made to back off and do unquestionably the safest route.
After a little elevation loss, we hiked to the base of the gully which leads to Stone Man Pass. In Roach's RMNP guidebook, he states some Class 3 climbing may be needed to climb this gully. However, the climbing in the gully is very easy Class 3 with very little climbing, if any at all (perhaps it's more Class 2+ than anything else, but he authored the RMNP guidebook before he created the class 2+ classification). Once at Stone Man Pass, we followed the standard route to the summit. Roach references a gap in a southwest-facing rib which must be found if the easiest route is to be had. Just prior to this point and continuing on up to the summit, a fair amount of class 3 climbing is required.
In Roach's RMNP guidebook, he states McHenrys is the toughest peak over 13,000' in the Park, although McHenrys, Meeker and Longs are all Class 3 climbs by their easiest routes. It's been too long since I've climbed Longs to compare McHenrys to Longs, but I think McHenrys is more difficult than Meeker due to the amount of climbing on McHenrys. Meeker seemed to have 4 or 5 spots which required some brief class 3 climbing. McHenrys seemed to involve sustained climbing and less obvious route finding over its last three or four hundred feet. Presumably, it is the last three or four hundred feet of McHenrys which makes it, as Roach states, "a test piece for peak baggers."