Short walks in the Yumthang Valley are highly recommended.
Don't forget to take a walk through the towns in the night. Its dark, a few light bulbs are the only source of light, its creepy but it is something which you cannot find in the cities. All you can hear is the stream of water flowing.
tours
The region of the Yumthang, Yumesamdong, Gurudongmar and Chopta Valley is the only part of North Sikkim that is accessible for tourists. Since North Sikkim is an area of significant military presence bordering Tibet, tourists may only visit with a guided tour, who must arrange a travel permit. Most organised tours are for 2-3 nights, costing $30 USD per day.
There are many travel agents who organize North Sikkim tours. A typical itinerary would be
Day 1: Travel from Gangtok to LachenDay 2: Travel to Chopta Valley and Gurudongmar early in the morning and return to Lachen, move to LachungDay 3: Travel to Yumthang Valley and back to Gangtok.
However, customized trips only to Lachen/Gurudongmar or Lachung/Yumthang Valley is also available.
It takes about 7 hrs to travel from Gangtok to Lachen. The journey is very beautiful, don't forget to stop your vehicle in between to take snaps. The series of Buddhist white prayers flying from long poles create spectacular sights.
There are two major towns in North Sikkim except Mangan, the district capital. These are Lachen and Lachung. The road to both these towns are same except for the last 30 km where they bifurcate. At the junction is a small dhaba serving amazing tea, samosas and coconut based sweets. Don't forget to try them out.
Both Lachen and Lachung are sleepy towns with very few local population. Lachung is more developed than Lachen. A series of hotels with basic facilities have sprung up. There are not many shops around which sell Beer and hard liquor but basic brands, so you better carry your drinks if you have expensive tastes.
The journey is long and tiring, but the scenic beauty will help you forget all this.