English is widely spoken, most of the guides and drivers understand Hindi as well although Nepali is the most widely spoken language.
Entry to North Sikkim is only possible on a guided tour, and a travel permit must be organised in Gangtok 1-2 days prior to travel. You would need a copy of your photo id card and 2 photos to obtain the permits for North Sikkim. All travel is by 4-wheel-drive as the roads are subject to frequent landslides. The terrain is very difficult and cold. Make sure that your tour operator is giving you cars in good condition. Mostly Boleros and Scorpios are the safest bet although Sumo Victas also ply. Nevertheless, the journey into the valley is stunning.
Lachen to Gurudongmar Lake. This is one journey which you will never forget. Journey from Lachen starts early at 5 am. Its mostly dark at that time. As you start climbing, the sun rays hit the snow peaks creating spectacular mountains of gold.
The only halt is at Thangu at 13000 ft where a single restaurant will serve you tea, bread butter (the bread has to be carried by the travellers) and maggi. You get to sit around the earthen furnace. Socks made from Yak wool and rubber boots are available on sale/rent.
The journey ahead is into the land of frozen rivers and chilled waterfalls. After about 16000 ft till Gurudongmar is mostly flat land with mountains on all sides. Its a high altitude desert, hardly any vegetation and very stony and dusty. You have to make your own roads here and its very easy to get lost. Because it is a plateau, it is very cold as chilled winds come down the frozen mountain slopes. Don't exert much as you would be gasping for breath at this altitude.
Gurudongmar lake at 17100 ft is mind blowing. In winters, the entire lake is frozen except one corner which is considered to be very sacred. Army jawans are always there to offer help. One should not miss Gurudongmar Lake in the north Sikkim tour.
The Yumthang Valley beyond Lachung is the major tourist attraction in the region. The colourful rhododendron bloom (May-June), soaring snow-capped peaks, and herds of wandering yaks makes this an idyllic location. The valley has a thermal spring, although the water can get quite dirty. The Lachung Gompa is the region's largest Buddhist shrine, located on the hillside across from Lachung.
Yumesamdong, Zero point from Yumthang Valley.
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.
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 Lachen Day 2: Travel to Chopta Valley and Gurudongmar early in the morning and return to Lachen, move to Lachung Day 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.
Simple Nepali, Indian and Tibetan food is offered at most of the guesthouses. The Tibetan momos (dumplings) are a must.
The hotels serve simple yet good food at Lachen. You can try out Wai Wai noodles, a brand of noodles widely available there.
Also, don't forget to try lopchu, a sweet made from milk and sugar. Its addictive.
Sampling the local millet beer (known as tongba or chang) with the locals is a great way of soaking up the atmosphere in Lachung. The Sikkimese beer "HIT" is popular for its high alcohol content.
Provided you stay away from military zones, there are few safety concerns in the region. Theft is uncommon.
The journey to Gurudongmar is into very high altitude and cold zones. Many people experience headaches because of lack of oxygen. Don't exert yourself too much and drink lots of water. If you are having kids with you, please be careful. The roads are steep and winding and nausea is very common.