GRAB is Thailands equivalent of Uber Eats / Lyft. This will be your go to if you prefer not to take the train system. Thailands train system is state of the art and a great way to get around, but can be confusing if you do not speak the language.
Climate
Thailand is warm and humid. December is the best time to travel. There could be scattered rain showers that last for a few minutes. Pack as you would if you were visiting Florida!