Apply for non O visa from Australia online. I was quoted about $300 aud to do this via Visa agent in Melbourne if the online thing is difficult for you, (some people have virtually no computer skills), this is a 90 day visa when you arrive in Thailand go to your local immigration ask them for extension of stay requirements follow their list.
if you want to base your decisions on what people told you that's on you. Don't forget they may be biased opinions or not truthful eg a person not telling you the reason they had hard time was non-compliance