You plan on moving to Thailand the rest of your life and you want to know how far your US dollars will go?
What baht rate do you use for your calculations?
From 1957 to 1997 (40 years) the thb rate averaged under 25 THB to $US 1 dollar.
1997 was year the market crashed spiking the baht causing a one time anomaly.
From 2000 to current (23 years), the THB has stayed above 30 to the dollar.
If you are planning on moving to Thailand, I think a safe bet would be to set your financial calculations on 30 thb to US $1 dollar.
Using the last 20+ years as a historic average, this seems to be a safe bet.
Take your US retirement funds in US $ dollars and multiply by 30. (example $1,000 US dollars a month X 30thb = 30,000 thb per month)
You can use this figure to determine if you can afford to live in Thailand or not.
Better to use this lower figure as a historic average.
If you can make your numbers work out at 30thb, you will be just fine.