US citizen coming to Thailand without a visa: whats the max I can stay?

Hi there, I’m heading to Thailand in a few days to take on a teaching position but the school has asked me to arrive first and then we will sort out the work visa.
I received notice from them just last week that the work visa application process can take up to 60 days, so it looks like the 30 days I’m allottedas an American with no visa may be inadequate. As I’m leaving the USA so soon, I don’t have time to secure the 90 day tourist visa. Does anyone have any knowledge about how to max the 30 days, for example can it extended, or can I doa visa run to another country, etc?
I’m also concerned because my return ticket is in 6 months time, which I’m afraid will make no sense to customs/immigration, or the airline for that matter. Will they even let me in the country with a return this far out and only a 30 day stay? Should I purchase a cheap flight out on AirAsia just so it makes sense on paper?
Any and all advice on this would be greatly appreciated. Thank You!