The short kora takes less than an hour (roughly 4km) and is unmissable. Try to tag along with some pilgrims and do one circuit at dusk, when the light on the lake is magical. If you have enough time, it’s well worth also hiking up to the top of the western hill for good views, especially at sunset.
The main kora path leads off west from the accommodation area, past Tashi Dor Monastery to a hermit’s cave hidden behind a large splinter of rock. The trail (now a 4WD track) continues round to a rocky promontory of cairns and prayer flags, where pilgrims undertake a ritual washing, and then continues past several caves and a chaktsal gang (prostration point). The twin rock towers here look like two hands in the namaste greeting and are connected to the male and female attributes of the meditational deity Demchok (Chakrasamvara). Pilgrims squeeze into the deep slices of the nearby cliff face as a means of sin detection. They also drink water dripping from cave roofs and some swallow ‘holy dirt’. It's a great place to explore if you bring a torch (flashlight).
From here the path curves around the shoreline and eventually passes a group of ancient rock paintings protected by blue railings. Pilgrims test their merit nearby by attempting to place a finger in a small hole with their eyes closed. At the northeastern corner of the hill is the Mani Ringmo, a large mani wall, at the end of which is a chörten with a chakje (handprint) of the third Karmapa.
There are several other great hikes around Tashi Dor. If you have time, it's worth walking to the top of the larger and less visited of the two hills to the east (two hours return). There are superb views to the northeast of the Tanglha range, which marks the modern border between Tibet and Qīnghǎi (Amdo). Morning light is best here. You can also walk around the base of this larger hill in about 2½ hours.
For the seriously devout there is a pilgrim route that circles the entire lake. It takes around 18 days to make a full lap, staying occasionally at small chapels and hermitages along the way.