you can't use a regular Thai driving license on its own, you'll need the International Driving License and The Thai Driving Licence, for vehicle hire, and police producers. Also insurance companies (unless a hire car, ie Enterprise etc) will need to be notified that a driver using the vehicle is using a Thai International Drivers License.
Non-Immigant O-Visa as you have a Thai Wife, then apply for 365 days extension for Retirement, Terms and Conditions apply.
Use 'Thai Visa Centre,' they take the hassle out of it all. Remember your 800,000 bt has to be in 'your' (not joint) Thai Bank Account for xx Months, or proof of your pension, that it meets the required amount