I replied to this request before as has many others. So, the information necessary is pretty adequate in detail, but no one seems to have a handle on the REAL decision being made by the ajudication officer. Remember the law governing this application process is backward from the normal 'criminal law' in the US, ala the defendent is innocent until proven guilty. It is vice versa when coming to a VISA.
With VISA applications, the applicant has to prove that he/she has serious reasons for returning to Thailand, such as family he/she is respomible for, a self-sufficient job (or business), and and tyically a sponsor (and not a husband or wife) in the US. As a matter of fact, it would behoove you to travel to Thailand and be with her for the period of time of the application process. So, essemtoially you are 'out of the picture.'
If you, the husband, are the sponsor, the officer immediately is concerned that the wife WILL NOT return to Thailand but stay with her husband and disappear into the country somewhere. If her business is one that she could just stop operating because it is not critical for her livelyhood (you are the husband and you can easily suprt her as you should.)
Where is the family? Any critical requiremenets like children that cannot leave? older parents that she is required to maintain their living standards, provide them living expenses?
This seems to be a very hard story that has to be developed to convince the ajudication officer that she has to come back to Thailand.
Over and above, you don't indicate where she lives in Thailand. If Vientianne is in close distance, it might be easier getting a tourist VISA there from the US Embassy than in Bangkok.