Yes you can use the bus in power wheelchair, you have a ramp and one special place for the wheelchair.

All the buses are accessible in the city.

Hi,

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,… Read more

Hi,
the island is closed in this moment for its protection.
The arrival of thousands of tourists by boat in this closed bay is a disaster for the local ecosystem.

In any case, nothing is planned for people in wheelchairs.

For more informations http://www.livingit.euronews.com/2018/10/25/the-beach-is-closed