You arrive at Chiang Mai, most likely on a connection through Bangkok — the domestic leg takes about seventy minutes and runs a dozen times a day. Your guide meets you and it is twenty minutes into the old town. Nothing else is fixed today. The moated square is walkable end to end in half an hour if you would rather start on foot than sleep.

The old city on foot and by songthaew. Wat Chedi Luang, whose brick chedi lost its upper half in an earthquake in 1545 and was never rebuilt; Wat Phra Singh, the principal royal temple; and Wat Chiang Man, the oldest of them, founded in 1296 when King Mangrai laid the town out. Late afternoon on Doi Suthep — 306 steps beside the naga staircase, or the funicular if knees object.

A morning at a sanctuary in the Mae Taeng valley where the elephants are neither ridden nor made to perform: you help prepare food, you watch, and you keep your distance when they want it. In the afternoon we drive east and up to Mae Kampong, a village at about 1,300 metres that grew on fermented miang tea and now lives on coffee and homestays. We eat there before the road down.

Ninety minutes south-west to Doi Inthanon, at 2,565 metres the highest point in Thailand. The summit is a flat forested hump with a shrine to the last king of Lanna; the walking is on the Ang Ka boardwalk through dripping cloud forest. We stop at Mae Klang Luang, a Karen village growing coffee on terraces that replaced opium. From March into April the view is often lost in smoke from field burning, and we say so rather than promise otherwise.

Three hours east with stops. Wat Rong Khun, the White Temple, is a private work by the artist Chalermchai Kositpipat, begun in 1997 and still unfinished; the murals inside are contemporary and deliberately unsettling. Baan Dam, the Black House, is its opposite — the late Thawan Duchanee’s compound of dark teak halls filled with hides, horn and bone. We check in at Chiang Rai in the late afternoon and eat together.

North to Sop Ruak, where the Ruak river runs into the Mekong and Thailand, Laos and Myanmar meet at one point. The Hall of Opium, funded by the Mae Fah Luang Foundation, is a serious museum and takes a good hour — the trade, the wars it caused, the addiction that followed. We go out on the Mekong by boat, then walk the ramparts of Chiang Saen, a Lanna town walled since the fourteenth century.

Up into the border hills to Mae Salong, settled in the early 1960s by soldiers of the Kuomintang 93rd Division who crossed from Yunnan and were never allowed back. Mandarin is still spoken in the morning market and the crop is oolong; we taste it at a family plantation. In the afternoon we drop to Doi Tung for the Royal Villa and its gardens, built as a crop-substitution project by the late Princess Mother.

Three hours west on the Mae Kachan road, with a stop at the hot springs where the eggs are boiled in the spring itself. The afternoon is free: the Sunday walking street if the day falls right, Warorot market if not, or the Lanna Folklife Museum opposite the Three Kings monument. We finish with a northern meal, khao soi included — a curry noodle dish the north makes and nowhere else does properly.

A transfer to Chiang Mai airport when your flight requires it, twenty minutes from the old town. Connections to Bangkok run all day, and there are direct services to Kuala Lumpur, Singapore and several Chinese cities. If you would rather carry on, Luang Prabang is a ninety-minute flight from here and we are happy to join the two trips into one.