@Gene *********
my advice would be to just hold fire on your plans for a couple of weeks. The plan is that Hua Hin will have its own Sandbox scheme starting on the 1st November. As of today there are no confirmed details of that scheme. The details will be agreed in October.
That will mean when you come in January you will be able to travel directly to Hua Hin. For the first 7 days you will need to follow the rules of the scheme which will be similar to the Phuket Sandbox. That is book a SHA+ hotel, have 2 or 3 COVID tests and instal an app on your phone.
After 7 days you will be free to do what you want.