@Rob ********
IF you're not interested in the "retirement" or marriage visas you almost just shoe horned yourself into a year-long, multi-entry Non-Immigrant Type O-A (Long Stay) visa (which is issued for the purpose of retirement for people over 50) :O
You get it from the thai consulate in your country BEFORE you wing your way here. It requires a police background check, a medical certificate, you showing proof of funds using your bank account in your country AND proof you carry the minimum mandatory health insurance requirements (OPD 400k / IPD 40k).
In the US you can get it from only FOUR thai consulates; Chicago, New York, Los Angeles & Washington DC.. Depending on where you are in the US you might have to use a specific one of those consulates.