You will need to go to Bangkok where the stadiums are (lumpinee, rajadamnern, om noi). Look at getting into one of these gyms…

- Kaewsamrit gym
– Sasiprapa gym
– Por Pramuk gym
– Tiger Muay Thai

The main thing to remember is to find a place that accepts foreigners, a lot of the best traditional Muay Thai gyms are exclusive only to Thai people.

Make sure you are ready I’ve trained with plenty of people who have been to Thailand to train and the heat and conditions can really ware your body down.

My advice for when you go is to make sure that your conditioning is up to par that way you will not get tired and get the most for your money while training.

I second your advice @bennihan