I'd stay in Samui, if you're into the money, teach online, but maybe fewer hours. I'm also quite sure there's poor schools in the area that you can donate your time to.
Also if the school has a 12 month contract, take it as there's tons of holiday time built into the Thai school schedule. Finish school at 3:30-4:00, then start teaching in the evening, when school's closed, you've got time to travel and do your online classes on the road.