Bangkok (2 days) e.g, grand palace, chaophraya, markets
Chaing Mai (4 days) e.g. elephant park, cooking school, doi suthep
Khao Yai National Park (2 days) e.g. trekking, wildlife
Khao Sok National Park (3 days) e.g. tubing, canoeing,
Koh Samui (5 days) e.g. swimming, snorkelling, Ang Thong Marine Park
May try and spend a half day at Ayutthaya between the national park visits. Anything major missing?
Any thoughts appreciated!