I don't know where you heard that information but here is a step by step process of obtaining visa, from my experience and what I've heard:
1. The entity you are going to work for or work with has to provide some documents to you. For my case, they are a letter introducing itself to the government and an letter inviting me to work at the organization.
2. With the documents provided aling with some other documents required and application, you can go to a Thai embassy or consulate.
3. Once you enter the Kingdom of Thailand, there are four clocks that starts ticking simultaneously: TM30, 90 days report, work permit, and visa extension. Now, the government agency that are responsible for these four things are different. However, failure in completion of the first three will stop you from getting visa extension.
3A: TM30 is Registration for your landlord or house owner to tell government that you live there. The law says that it has to be done in 24 hours of you arrival. However, some immigration office are very lenient.
3B. 90 day report: If you stay in the Kingdom for 90 straight days, you need to report yourself to you local immigration office.
3C Work Permit: Apply it at you local labor department office after you arrive in the Kingdom. If I am not mistaken, it's within three months of entering the Kingdom.
3D visa extension: getting visa extension means you need to go to your local immigration office with a lot of papers and work permit.
Henry Durrant Two reasons. One, because she is volunteer and may not be renting a house or living in a hotel, and therefore, house owner may or may not have the knowledge of TM30. Second, since it's her first time, it's better to be cautious. Know what it takes, do and don't.
If I were you, I would get TM30 first, work permit, and start working on papers needed for extension ASAP, particularly the photo required in the application.
What Mr. Tod Daniels said is a counter located before immigration checkpoint and in close proximity. It may not
have an officer on station, as it is sometime the case at Chiang Mai Airport. But if you stood in front long enough, someone will come and take care of you.
My answer to your first question is different. Applying for Re-Entry couple of days ago, my answer to the first question is the last visa extension. I was told this by an Immigration officer at Chiang Mai Airport.