Enter the National Park at the Beaver Meadows Entrance, take your first left onto Bear Lake Road. Continue down Bear Lake Road until you get to the Glacier Gorge parking lot and trailhead.
Once on the trail, follow signs to Mills Lake, and on to Black Lake. Black Lake is 4.7 miles from the trailhead. Here is where you make you decision on how to get to Stone Man Pass.
You can head left (south) from Black Lake, which takes you to the shelf directly above the lake to the West. Turn to the North, where McHenrys and Stone Man Pass (South Southeast of the peak) will be clearly visible. The trail will lead you close to the base of the Spearhead, and close to Frozen Lake (this is a wonderful lake and is worth a short side trip if you feel you have the energy). The trail will lead you across increasingly steepening slabs of exposed granite to the base of the gully that leads to Stone Man Pass.
Another option is to head North, along the forested banks of of Black Lake. This will lead you up a steep slope to the base of the Arrowhead. From here, pick the best way up the layers of small cliffs (7 to 15 feet high) to the shelf North of Black Lake (this can be VERY tricky if it's icy!!). Once on the shelf, head to the base of the gully to Stone Man Pass. This will save you a good deal of distance at the expense of some MUCH steeper terrain.
The gully that leads to Stone Man is full of tiresome scree. However, it went by a lot quicker then I expected. This can also be full, completely, of snow well into July.
Now that you are at Stone Man Pass (and the Continental Divide), head right, Northwest, along a faint footpath, and keep a sharp eye out for the small (sometimes non-existant) cairns. Head steadily uphill, over large boulders, for a little over a quarter of a mile. You will then drop into a gully that will lead you to the summit. On this stretch of the hike, you can make it as hard as you'd like (at least class 3). There is plenty of class 4 to experiment with, and even 5+. Note that previous route finding experience will come in very handy.
You are rewarded with a perfect summit, and very unique views of surrounding peaks.
I would recommend bringing your typical long-day hike gear (good boots, layers, rain gear, plenty of food, water, etc...). Black Lake will be your last source of water for quite a while, make sure your containers are full.
In the winter, you will need an axe and crampons. The scree at the pass is difficult enough, with snow, winter climbing gear would be a must.
Again, make sure you dont forget the camera. You will want to remember this trek.
If you have information about this route that doesn't pertain to any of the other sections, please add it here.
Just a little side note:
This mountain is sooooo much fun to climb. There are distinct "sections" of the trek, much like Longs. Looking up at the summit form Black Lake is very intimidating, and when you stand on the summit, it is that much more rewarding.
I love this mountain because I was able to push my comfort levels quite a bit. I was able to try more class 4 and a small section that has to be 5+ (I'd be suprised if it wasn't). For me, that's huge!
I was also suprised at the small number of people that summit this mountain. According to the register, I was the 39th person to summit in the past year (counting "Jeffery Lebowski"). I didn't see anyone else until I passed a ranger just below Black Lake as I was heading back down.
Not only is it a beautiful mountain, but it is a more than rewarding experience while climbing...one that I will, no doubt, never forget!
FYI: the other major route is via McHenry Notch...a much more technical route, of which I know nothing about.