This is a great trip to do before or after the Langtang trek or you can also combine it with a trip over the pass to join the Helambu trek. Goisankund lake is sacred to both Hindus and Buddhists (the rock in the lake is said to be the birthplace of Lord Shiva) and is a site of mass pilgrimage in August each year. The views along the trail are beautiful - especially from Laurebina Yak and the walk not very difficult, though there is a significant danger of AMS at this altitude.
When you are in Kyanjin Gompa you really should make the effort to climb when of the many peaks that are around. The easiest peak is Kyanjin Ri at 4773m with beautiful views of the glaciers and Langtang Lirung, but even climbing up to the viewpoint before that, is well worth it, and the views are equally spectacular. You can also climb Tsergo Ri at 4984m and Yala Peak at 5500m.
If you get the chance to hike up the Langtang Valley to Kyanjin Gompa, and even beyond, it should not be missed. It is a beautiful 6/7day walk, either starting in Syabrubensi or Dhunche. I think the walk to Lama Hotel from Dhunche going via Thulo Bharkhu and Thulo Syabru is much nicer than going there straight from Syabrubensi, it is also a shorter bus ride! The walk itself is not very difficult (I managed it when I was 3 months pregnant!) and only has a couple of very steep uphill sections. The walking days, too, are not so long, on average, 5 hrs a day. The mountain scenery is beautiful and the people fantastic. The view at Kyanjin Gompa especially of Langtang Lirung, is one fo the best that I have seen anyway in the Himalayas, and best of all, as the third most popular trekking region in Nepal, it is never that crowded.
If you are of the curious kind, proceed along the road to the lead mine at the foot of Pabil mountian in the Ganesh Himal. You may be able to hitch-hike here by a truck going to the mine, or you can trundle up the zig-zagging road. An interestin diversion will be to walk one of the ridges or spurs back toward the Trishuli Bazaar area.
Beware, though, a village along the route was entirely abandoned because of bad spirits. Everybody relocated, and the story went across the world in newsmedia.
At least check on the maoist situation beyond the Trishuli watershed...
I guess this is a gentian, but I will leave this toi the experts. Once in a while, not only when there's a steep uphill, check the ground foir beutiful alpine flowers. They hug the ground, most of them, but remain you of their presence by very strong colors.
The Langtang area is famous for its flora. Perhaps, if you are interested, bringing a flower book from Pilgrim's could be interesting?
This little ... mouse-hare! looks just like its name and is a trustful companion in the high alpine country. It is bigger than a mouse, more like a rat, but very cute.
If you are still and apparently benign, it will quickly come near and scavenge bread crumbs and nuts and rasins etc. This one was right at the Laurebina La.
Up from Laurebina Yak and the resting houses the uphill levels out, the ridge gets rather narrow (not at all scary) and there is a new chorten made right there. It's a concrete structure, not very nice in fact, but here you can at least lean your tired back to the chorten wall, sit in the warmth of the sun or out of the wind and enjoy unbelievable views all around: Langang Lirung, down into Langtang Valley, the Chandanbari, Trishuli Valley, into Tibet and over to Ganesh Himal and beyond.
Up at Laurebina Yak (as well as higher up on the ridge) there is a very good view toward 7200 m Langtang Lirung. Bring binoculars and study how the snow and ice clings to its steep faces.
At Laurebina Yak there is a seasonal possibility of getting food, drinks and acommodation of sorts.
From the ridges above Singh Gomba, Laurebina Yak and thereabouts you may have a good view of the mountain spurs of the Himalayan massifs of Ganesh, Manaslu and in the far distance the peaks of the Annapurnas.
The perspective of size dawns on you when you figure the Annapurnas are nearly 200 km away...
The Trishuli Khola runs from Gosainkunda lake and together with the tributaries Langtang khola and Bhote khosi from this same area Trishuli forms the long river that ends (in the name) at Mugling where it meets the Marsyangdi and forms Narayani River that again spills out into the Chitwan National Park.
Trishuli rushes past Dunche in a deep canyon, but higher up you can physically follow the Trishuli, now merely a mountain creek. Take the trail off the main road where indicated by a sign just out of Dunche "centre" and follow the trail into the valley. You are now on the right way toward Singh Gomba and Gosainkunda.
The trail maps indicate 5 hours to Singh Gomba, but I have done it with a big backpack without trouble in 3. That means you should have plenty of time to explore the beautiful forest that you walk through. Stop and look.
You feel they are so close you can touch them - the Ganesh Himal's outcropping and spurs across the Langtang khola/ Bhote kosi canyon below Syabrubesi.
There are many single peaks in the Ganesh Himal massif, and they are almost equally impressive, small and large. This must be the prefect place to just ramble and scramble around and be happy among the mountains.
The road continuing from Dunche further on to the lead mine below Pabil mountain brings you right up to the foot of them.
Look north from the little ridge above Sing Gomba or higher up toward Gosainkunda to see across and catch more than just a glimpse of Tibet. You can see the little plain where the settlement of Kyriong is, where Heinrich Harrer and Peter Aufschneiter spent some time during their 7 years in Tibet. There is talk about opening the border here (Rasuwa Gardhi) for tourism and building a road across - there are only a few km missing now.
The glaciers and mountains of this part of Ttibet are both harmonious and violent simultaneously - bring your bioculars.