Bountiful hiking opportunities radiate in almost every direction. For all-day or overnight treks, including to Huágàishén Shān (华盖神山; 4200m), all the horse-trekking companies and most of the hostels in town can arrange a local guide.
Southwest of Kerti Gompa is Namo Gorge (纳摩峡谷; Nàmó Xiágǔ), which makes for an excellent two- to three-hour (return) hike. The gorge contains several sacred grottoes, one dedicated to the Tibetan goddess Palden Lhamo, the other a stone-tablet-labelled Fairy Cave (仙女洞; Xiānnǚ Dòng), where monks sometimes chant inside, which gives the town its Tibetan name (lángmù means 'fairy'). Cross rickety bridges flung over the gushing stream, trek past piles of mani stones and prayer flags, and hike on into a splendid ravine. After about 30 minutes of clambering over rocks you reach a grassy plain surrounded by towering peaks.
A popular trek is the hike along the White Dragon River to the river’s source (白龙江源头; Báilóng Jiāng Yuántóu), where domestic hikers go in search of chóngcǎo (虫草), a coveted herb used in Chinese medicine.
Another lovely walk heads out over the hills along a narrow paved road from the stupa at Serti Gompa (you must pay admission to pass through) to the small village of Jíkēhé Cūn (吉科合村). This hike can be combined with the hike to the White Dragon River source. When you reach the village, simply follow the loop and then head down a dirt path towards the valley below. Watch out for local dogs.
For glorious views over Lángmùsì, trek up the coxcomb-like Red Stone Mountain (红石崖; Hóngshí Yá). To start, turn right one street back (heading out of Lángmùsì) from the intersection where the bus drops off.