From Lake Agnes ascend up the boulder and talus field to the Richthofen-Mahler saddle. If you go early in the spring an ice axe might nice to enable you to ascend the snow instead of the talus.
Scramble west to the summit.
Just kidding, here are a few more details: the first part is fairly easy. Stay on the ridge top or drop a little to the south side of the ridge when necessary.
Soon you'll get to the crux. There will be a significant notch blocking your way. The first challenge is to descend down to the notch. From the ridge top you can either descend down a steep, class 4 gully; or you can backtrack a bit and utilize the ledges on the south side of the ridge. When you get to the bottom of the notch examine the ridge. It can be a bit daunting, so if it doesn't look like your cup of tea you can bail down the gully to the south and then traverse the south side of the mountain and ascend up the south ridge (as Roach suggests in his RMNP guide).
If you want to continue start out on the north side of the ridge Make sure to check every hold as the rock can crack apart in your hands. About 50-75 feet up this steep climb regain the ridge proper and examine the south side. You should see the spot where the slope of the east side decreases. Climb up to this point and then leave the ridge proper to the south side. Ascend the easiest route until you regain the ridge proper.
At this point you've passed the difficult part. Scramble the rest of the way up the ridge to the summit. The remainder of the ridge will be class 3 punctuated with a couple of class 4 moves. Be careful to check all holds as the rock can be rotten.
Trekking poles and/or an ice axe can make the ascent up to the Richthofen-Mahler saddle much more manageable. A helmet is probably a good idea if you're climbing with a group as you will likely dislodge some of the loose rock along the way.
If you have information about this route that doesn't pertain to any of the other sections, please add it here.