on my last return to California Ibwas qyestioned at lenght by US immigration and quite rudely. Why have you been out of the country for 5 months? What do you do in Thailsnd? Why did you go yo Csmbodia and Vietnsm? Why do you still have a Green Card after 20 years? Why aren't you applying for US citizenship? Where did you stay when overseas ( I don't see how that is actually relevant). Who is at your home in California while you are away? It was bizarre.
I have a UK passport and an American Green Card and split time between the UK,California and Thailand. Maybe it my lack of permanent locale but I am always asked.
I have always been asked when flyin in from anywhere . Also it used to be de rigeur to be asked at immigration for your exit ticket . Maybe I look shifty and travels too much!
Jila is correct you have to apply outside the country amd I have read that the approval process varies in time from country to country. You also can't apply more than 3 months in advance and obviously need the 500k baht in a Thai bank plus health insurance.
Brandon, I would assume you can apply at any embassy outside of Thailand but my question is more about which courses are accepted besides Muay Thai which seems to be very popular.