This is the main trail to the summit of Gyaphelri. The trail below the summit ridge is extremely eroded and can be difficult to find in some places.
From Drepung Monastery (12,200')(see the Getting There directions on the main page), follow the pilgrimage kora (clockwise circumnavigation of a sacred object, in this case the monastery). Leave the kora around NW corner around where the kora turns left. The exact spot can be hard to find, but if you follow the well worn paths, you will eventually get to the main route.
Follow the trail up a prominent gully along the right bank of the stream. This is a view of the gully from above:
As long as you are proceding upwards (N), you are doing fine. The many trails eventually merge into one. The main trail becomes obvious and is even lined with rocks in some areas. You will eventually reach a ridge spur at 13,900'. This should take 60-90 minutes from the monastery. From here the trails makes a traverse East to the Gyaphel hermitage at 14,800':
You may some yak along the trail. Despite their appearance, they are very good natured animals. Make a lot of noise if they are blocking the way, and they will move out with surprising speed:
You can take the opportunity to socialize with the monks at the hermitage if you have time/inclination. From the hermitage, follow the switchbacks North toward the ridge looming above. You should be able to gain the East Ridge in about 60 min. Depending on the weather, you may now be able to see the summit:
You are now at 16,300' and have about a 1000' of easy walking on a gently graded broad trail. Relax and enjoy your surroundings - the trail is lined with a zillion of relics and devotional monuments:
Another hour or so brings you to the summit. The amount of devotional objects increases as you get closer to the summit. The summit itself is about the size of a football field and is almost completely covered with prayer flags, huge cairns, monuments and various personal items like shirts, various types of hats, shoes and gloves. It felt a bit spooky to be there - I was the only person there and the weather was ominous. At the same time, the place had a very spiritual feel:
Retrace your steps to the monastery.
Here is a view of Gyaphel and Drepung:
Be sure to follow the kora clockwise around the monastery to get back to the road.
Depending on the time of day, the monks may not allow you to come back to the parking area (the monastery closes at 4:30 PM). If that's the case, you may need to walk along the road to town and flag down a cab as soon as you see one. If it's early enough, you may be able to catch a cab or a minibus at the monastery parking lot.
Standard hiking gear depending on the season.