I am from the USA and have T-Mobile. They allow wifi calling and have free low speed data while in Thailand. If I use roaming it cost 25 cents a minute. Most of my Thai friends use Line or WhatsApp.
what happens if you have an accident while driving without a valid license? Will the insurance company cover your claim? I'm not trying to be a wise guy but I've heard insurance will not cover you without a valid license.
Look at the wattage of each appliance. Calculate your maximum concurrent load by adding the wattage of the appliances that will be in use at the same time. Buy a transformer with at least 20% surplus capacity.
Also, look at the cost of buying 220 volt appliances vs a transformer.
I don't have exact dates yet, but I'm planning to go over about the same time. I going to get everything planned in advance and start booking about two weeks in advance of travel.