here in the USA you can get an international drivers license through AAA, good in Thailand for up to one year, you show your USA drivers license your passport and the document from AAA with your picture on it , if your ever stop you just show them all the documents.
I cannot describe it any better I went there for a month ended up staying two months, ate some amazing food and really enjoyed the street food visited a lot of the markets they have all over Phuket and Laguna , made some incredible Thai friends .