as I said in my post I have been out of the country for a few years working in China and planning to return this summer. When I was last in Thailand, I used to be able to go to Laos or Malaysia once a year and get a one-year multiple-entry O Visa and all I had to do was show my marriage certificate and wife's ID card.
even to stay here on a retirement visa you need to maintain a minimum balance of 400k and a balance of 800k for a minimum of 3 months prior to your application. To establish a business you need a Thai partner who will maintain a controlling interest in the business, ie minimum 51%. These are the regulations. however, you can get a one-year multiple entry visa (based on your marriage to a Thai?) prior to coming, which will only require your leaving and re-entering every three months (a day trip to Cambodia and back would suffice) if nothing has changed recently. This is my current plan and worked for me for 10+ years.