Tips for a 18-day trip through Thailand!

Hey guys. How are you all doing?

Me and my wife are taking a 18-19 day trip to Thailand, in late November. As it´s our first time in Asia, we would like you to help us commenting on our first draft itinerary. Can you weigh in?

Days 1 - 3: Bangkok

Day 4: Ayutthaya

Days 5 - 7: Chiang Mai (is it possible to take a day trip to visit Chiang Rai?)

Day 8 - 9: Chao Mai

Day 10: Ko Muk

Days 11-12: Ko Phi Phi

Days 13-14: Krabi (Railay Beach)

Day 15: Hong Island

Days 16 - 18: Khao Sok (raft house by the lake)

Day 19: Bangkok

By searching online we decided to drop Koh Samui and Phuket; as this places are too crowded. But we kept Phi Phi because it seems a most go place when in Thailand.

What you say? Any thougths?

Thanks for your help.

Edited: 02 August 2018, 17:51