Yeah I’ve heard a lot about Phuket being over populated nowadays. What I can remember about there is it was very good for trips. I’ve never been to Chang Mai so that could be a possible.
My rough aim is to do 2 out of 3 areas between Pattaya and either Samui or Phuket. Probably 6 days in each. I’ve done all 3 before over the years but Phuket and samui were 30 years ago. Pattaya I have freinds who go for a couple of months so will be going there. Just can’t make up my mind about the other 2