Thailand 3rd - 16th Oct... guidance on schedule (Bangkok)

Dear All,

This would be a first for me to just take a bag and land in Thailand to travel around the beautiful country, see the beaches, do sea diving and relax a bit as well.

May you kindly advise me on the schedule below if seems fine. Also, thoughts welcome on accommodation, places I must see during my stay, if people want to meet me (I got lots of stories on my stay in South Africa, UK and India) etc. Am moving to London soon so people are welcome to continue our association and then come see me in the UK :)

3rd Oct - Land in Bangkok, spend the day and night there
4th Oct - Leave for Pattaya, spend 2 days and 2 nights (4th and 5th) there and do a bit of snorkeling, leave for Bangkok on the 5th in the evening, take overnight train from Bangkok to Chumphon
6th Oct - Ferry from Chumphon to Koh Tao, do sea diving course from 6th to 10th in Koh Tao
10th Oct - Leave from Koh Tao to Koh Samui, spend the night in Koh Samui till 11th afternoon
11th Oct - Leave from Koh Samui to Phuket, spend nights of 11th and 12th in Phuket
13th Oct - Take flight from Phuket to Langkawi in Malaysia, spend 2 days snorkeling/diving and nights in Langkawi
15th Oct - Fly to Kuala Lumpur, spend 15th night in Kuala Lumpur
16th Oct - Fly from Kuala Lumpur to Mumbai after spending the day in the city

Many thanks.
Piyush