Travelling to Thailand mid November... where should I go?

Hello everyone, my first time to Thailand from Canada for a business meeting in Bangkok in mid-November.

1) I won't have much time in Bangkok. Any tips on what to do while I am there?

2) I would like to travel to another destination in Thailand for a few days to enjoy the most gorgeous beaches (Again, timing is mid- November). Where do you recommend?

A bit more about what I'm looking for:

  • safety at a nice accommodation (female and travelling solo)
  • amazing snorkelling
  • yoga
  • Massages
  • Thai cooking classes

What I don't want: - tourist traps - Loud partying

Thank you in advance for any tips !