good advice in general, just one point about the phone. If you have an unlocked phone you can change your SIM card when you get to another country and use a local service. And some phones even have two slots for SIM cards so you can leave your home country SIM card in and add a Thai SIM card.
I agree with what you say it say, it happened to me yesterday. But I don't necessarily take her as American hating, maybe just a stickler for details. Geographically she's right, but culturally she's out of step with Thailand.
David Broadfoot It worked for me applying inside the Krabi immigration office. Maybe the online poster was only talking about applying outside the country. When it comes time for the first extension I will have more than one year of deposits to show.