There are many ways to get from Chiang Mai to Kengtung by bus, car or plane.

Bus, drive7h 2m
Chiang Mai

4h 45m by Bus, every 4 hours

2h 17m by Car(160.2 km)

Chiang Mai is the most beautiful between November and March of the following year, the coolest and most pleasant weather season, morning and afternoon will be cold, sunny afternoon but not harsh.
This time there were many big festivals like Loy Krathong, Yi Peng in November, the February Flower Festival, and the beginning of the year with the blooming sakura season. Therefore Chiang Mai Thai tourists at this time are very crowded.
May to August, tourists are a little less crowded, because this is the rainy season in Thailand, to ensure the safety of tourists, some places will be temporarily closed.
The ideal minimum time to explore Chiang Mai is about 7-10 days. For the first-time writer, I just want to stay at the end of the visa period. 😛 If I go on a long trip, I can go to Chiang Rai, Pai, Lampang, Mae Hong Son and Sukhothai to make a North Thai combo.

According to my experience of traveling to Thailand, it is different from Bangkok, the traffic in Chiang Mai is somewhat softer, and it is also easier to travel with lots of options:
+ Song Thaew (short card):
It is such a popular means of transportation that if in any picture has the silhouette of a car but is red, it is not necessary to say that you are in Chiang Mai Thailand. Anyone who comes here should sit on the couch once called to travel to Chiang Mai.
To call a busy car, just stand by the road and wave any red car you see, the driver stops and asks where you go, if in the road that the car will pass, the driver will OK and say you Get in the car, otherwise they will refuse and you wait for the next car to appear. Rest assured that it is as much as it is in the cloud, less than a minute you can sit on another car.
Note that before getting on the bus, remember to ask for the price and bargain, normally the price for 1 person will be around 20-40 Baht / trip.
+ Tuk tuk:
If you want to try the thrills, travel to Thailand in the adventurous style and be wriggled in super narrow lanes, then take a car Tuk Tuk. Although the speed is not “terrible” as in Bangkok, but sometimes the sharp cornering, braking the driver’s sweetness is enough to make you thirsty.
The writer has experienced how to turn off from the A road to the driver’s road B by driving into the parking lot of a high-rise building and then straightening up without speed at all.
As a means of branding of Thailand, the tightness of cutting is also higher than that of many. Need to pay the price before sitting on the car, about 6km for about 6 Baht / person is fine.
+ Motorbikes and bicycles:
If you go near you can rent a bicycle (50 Baht / day), go a little further, rent a motorbike (200 – 250 Baht / day, not including gasoline). You can rent a car right at the hotel or hostel that you live in or go around to see a bit of a newer, more beautiful car rental to choose to be on the “virtual live” picture. Car rental procedures will require you to deposit money or retain your passport when signing a lease.

Note that the Thai side is different from Vietnam, going to the left on the left, if you rent a car, you need to be careful, especially motorbikes, too absent-minded to encounter Thai police, but you cannot submit a driver’s license. The trip is also a bit funny. Although rare but not without, especially on major holidays, the police are very crowded to control security.