What to sort out before you fly

On most journeys, never above 2,320 m. Darjeeling is 2,045 m and Gangtok 1,650 m, where altitude sickness is rare and most people notice only a shorter breath on the stairs. Height starts to matter on the day trips, Tsomgo at 3,753 m and Nathu La at 4,310 m, and on the few high nights at Lachung, Zuluk, Phobjikha, Sandakphu and the trek camps. Those always follow lower nights and never the day you land; how each high day is built, and when we turn back, is set out in the altitude rules above.

Pack for nights near 4 °C and days around 14 °C, and colder still before dawn at Tiger Hill: thermals, a proper down jacket, a woollen hat, gloves, thick socks and slippers for cold floors. Days are bright and dry, so bring sunglasses and sun cream too. Many older houses have no central heating, so we ask each house about heaters, fires and extra quilts for your room before you arrive.

Yes. Our booking terms ask every guest to hold cover for cancellation, medical care and evacuation in the mountains, and Bhutan expects its visitors to be insured. The number that matters is the altitude limit: a standard policy often stops at 3,000 m, which is below several of our days, so buy to the highest point on your own itinerary, listed above, and ask your insurer in writing about a helicopter flight. We need the policy number before a trek crew is confirmed.

In the towns, yes; on the high roads and in the gorges, not reliably, and the table above says which network reaches where. Buy a local SIM in each country rather than roaming, because an Indian number roams poorly and expensively in Bhutan and Nepal. Tell whoever is at home that a day at Tsomgo, on the Zuluk road or on the Singalila Ridge can pass with no signal at all, and that your messages will arrive in a burst when the car drops back into a valley.

In the towns, yes, and the table above says where. What a table cannot tell you is how much cash to keep in your pocket: enough for offerings at a shrine, a khada at a gompa door, a stall at the haat, a porter and the tips you choose to give. Draw it in Darjeeling, Kalimpong or Gangtok, because the machines at Kurseong, Ravangla, Yuksom and Zuluk can be empty when you reach them.

By deciding the rooms and the route before you arrive, not on the day. One outing a morning, a long lunch after it and a free afternoon do more for a slow walker than any lift. We ask each house for a room near the lift or on one floor, choose monasteries and viewpoints the car can reach close to the door, and say plainly which places cannot be softened: Taktsang is the clearest, where a pony carries riders only as far as the halfway cafeteria and the walk on to the monastery gate is on foot.

It is your choice and never expected on the day. In India we suggest ₹500 to 800 a day for a driver and about ₹500 a half day for a guide. In Bhutan, a common rule of thumb for one or two guests is US$8 to 10 per guest a day for the guide and US$5 to 7 for the driver. Most guests hand over an envelope on the last day.

Ask your GP or a travel clinic four to six weeks before you fly, and read the country pages named above. We give no medical advice and your own doctor decides what you need. No certificate is asked for on any of our routes, unless you arrive within six days of leaving a country with a risk of yellow fever. Treat the tap as undrinkable in all three countries: refills travel in the car, every house puts drinking water in your room, and the tea arrives boiled.