For those that are unaware, the King of Thailand was highly revered in Thailand and his death, many Thai's commented to me, was like they had lost their own father. He is the longest serving monarch and almost all Thais have never experienced any other monarch. So please be aware that for many Thai people, this is a very poignant and sad time.
Please be very respectful of the Thai people's feelings and please avoid asking questions regarding the old and new king. It is easy to offend Thai people in this regard and Lese Majeste (a law prohibiting perceived negative comments and actions) is still enforced here.
Especially in the towns and cities, be respectful with your clothing, at religious venues (as always) and near Royal buildings, wear sober and respectable clothing (cover shoulders and long trousers/skirts).
The plans and what is/is not allowed are changing constantly, but be aware that at most holiday beach destinations there will probably be a lot more lax observance of this period. I fully expect Bangkok to be insanely busy over this period, all the Thai airlines are massively increasing their flights in and out of Bangkok, to accommodate the amount of Thais wanting to be at the funeral. So if you want to get out of the crowds and not experience this historic event, then I would be planning your exit from Bangkok soon (I expect flights to increase in price).
I have just heard today, that the Full Moon Party in Koh Phangan is cancelled in October, which is not a surprise, I expect most extravagant parties in Thailand will be cancelled or significantly toned down in respect of the king. Many may still go ahead, but over the funeral week, starting on the 21st October, we believe that all parties and shows will be stopped.
For sure there will be alcohol free days, especially on the 26th October 2017. However, often large hotels are exempt from some of these days and there are always 'mom and pop' shops willing to sell alcohol (7/11 will not).
I think all over Thailand you should expect to see many Thai's wearing black or white as a sign of respect, but as I previously stated, outside of main towns and cities, you should still be able to enjoy your holiday with only minimum impact.
Finally this is a historic event and it does deeply impact many Thai people. Please be aware of this and act appropriately.
Below are 2 videos we made of our islands dedication to the king on his passing. The second one has a speech (in Thai and English) and then the National Anthem, very beautiful to listen to.