The Meridien and Shangri la hotels have specially adapted rooms. Easy access to the Night Bazar just a few meters.
There are wheelchair accessible buses in the city and from the airport just 20 baht.
The problem in Chiang Mai is the not very accessible sidewalks and the traffic, that is dangerous in Thailand.
It’s better to be accompanied, to go from one place to another and not too close to the road.
For more informationthailandehandicap.com
It is in french sorry, but you can translate directly