And before it all goes out of order, I close it down.
The question is about 90 days, if you like to stay 1 year living, working, relaxing or doing something else, apply for the visa that fits that purpose.
Going in and out on regular basis using the Visa Exempt Entry could end up in a questionnaire of the Immigration Officer just doing his job.
There is no crack down on Volunteer visa, unless you bought the visa in a place you never visited and work for an organization you never heard of.
The Extension of Stay based on unable to travel is maximum 60 days and application ends on 25 July, unless the program gets extended it will not get you into November.
You can visit a neighbor country and apply there for a Single Entry Tourist visa which gives you 60 days and can be extended once with 30 days, this could be enough time before you leave the country.
Get the Non Immigrant B visa and get a 1 year Extension of Stay is an other option.
There is no Extension of Stay based on future work. If you did not find a new job or your employer can not get the documents ready on time, the option is to go abroad and apply for a Single Entry Tourist Visa which gives you 60 days or come back again without visa for 30 days and hope you get the documents from your employer with minimum 15 days on your stay to convert to a Non Immigrant B visa.
And just for information: The price to apply for an Extension of Stay is 1,900 Thb.
Price is the same as it is the price to apply, it does not depend on the term of extension, you can get 1 year, 90 days, 60 days, 30 days, or even 7 days to leave the country.
The under consideration period is part of the maximum amount of days you can get on this application and is used because the officer can not decide himself and have to sent it to his superiors to consider your application.