The north ridge on Lone Pine Peak is a classic Sierra ridge climb. Unlike many established rock climbs, there is no single "correct" route. The topology of the ridge is rather complex. Blocks, towers, and deep notches present obstacles to forward progress that may be turned in a variety of manners, ranging from easy (class 3) to hard (class 5.double-digit). Rather than worrying about whether you are "on route", ask yourself if you like the route you are on. If so, carry on. If not, look for alternatives.
The approach depends on how much of the ridge you plan to climb. The standard approach follows the Meysan Lakes trail until just before Little Meysan Lake where the trail levels out close to the stream at around the 9,500 foot level. Directly east you will see a rather poorly defined chute marked by a lone tree on its lower right side. Scramble up the chute (loose class 2/3) to a notch, then traverse from the notch to a broad talus gully. Cross the gully to reach the north ridge proper.
If attempting the complete north ridge (it's been done in a day!), start either at the pullout at the start of the switchbacks on Whitney Portal Road and cross the creek to the toe of the ridge, or at Lone Pine Campground, and follow the stream on the south side until reaching the ridge. Scramble up the ridge for several thousand feet until around 11,000 feet the climbing transitions from talus to easy rock.
Whichever approach is used, scramble up steepening slabs (up to class 4) to a notch where the climbing becomes obviously technical.
The ridge is a complex affair with many gendarmes, steps, notches, knife edged portions and ledge traverses. A large number of variations are possible. It is probably possible to find a way that keeps the difficulties to fourth class or below, though one would not spend much time on the ridge crest. Tackling some of the towers directly is likely to involve climbing well above the 5.10 level. The simplest description would be to simply say "follow the ridge". It is a good challenge in route finding.
However, for those preferring to follow more detailed instructions, there are a few options. Some (myself included) have found the rather lengthy description in Secor to be confusing. Alois Smrz offers this improved description:
"From the notch, go down and left some 40', climb 5th class crack slanting left. Climb 4th class pitch toward the huge, sharp flake above. Go left and down, follow ledges to gully system, which leads back up toward the crest of the ridge (3rd,4th). The ridge soon brings you to the Second Tower. From the notch, move right 50'. Climb 5th class steep face/ramp to 5.7 layback with old, fixed ring pin. Belay at a platform on the right. Move 10' right, climb awkward (5.7?) offwidth.
"Continue up for two pitches to top of the tower. Traverse along the crest of the tower. Descend to the notch. Third Tower. From the notch, move left and down into large gully (20'), climb 5th class crack/steep face to a ledge on the left side of the arete. Two more 4th class pitches up and right bring you to the crest again. Traverse along the crest. Downclimb south side of tower to notch and final summit pitches.Summit Pitches.Twenty feet left of the notch, climb up 6-8 pitches of 4th and easy 5th directly to the summit register.
"Please note: To reach the notch of all the towers, downclimb 4th class terrain, no rappelling is required."
Joe Lemay has described a somewhat easier alternative:
"From the notch, go down and left some 40'. Rope up. (Second Tower.) Climb 5th class crack slanting left for a pitch toward the huge, sharp flake above. Before the flake, go left (east) around buttresses following ledges into a gully that leads to a notch in the ridge. (Third Tower.) 200 ft. before the notch, follow 3rd class ledges with some short 5 class moves up to the top of the tower. Downclimb into the notch on the west side.
(Summit Pitches.) Rope up. There are two options. 1. Traverse right on loose ledges, then up just right of the crest of the ridge for ~5 pitches. 2. Climb up to the top of the notch then twenty feet east and down from the notch. Immediately climb a short 5.7 hand/finger crack, then five pitches of 4th and easy 5th just right of the crest of the ridge directly to the summit register."
The most straightforward descent is via the northwest slopes. Follow the south ridge until it is obvious that you can easily drop into the large bowl that leads back down into the Meysan Lake drainage. Be careful about dropping in too soon, as the first chutes you come to will probably leave you cliffed out. Pick up the trail again in the vicinity of Grass Lake, and walk back to Whitney Portal. Class 2.
The route is often soloed with nothing more than approach shoes or rock shoes. Unless you are confident free soloing 5.7 rock with significant exposure, plan on roping up for at least part of the climb. A 50 m rope, single set of cams, a few small nuts and plenty of long runners will suffice.