Had you taken the time to go to immigration and start asking questions you would have known. It's always my first port of call, because different offices have different rules. Now that your money is seasoned if I understand correctly, it should be straight forward applying again you have done it before . Good luck. I think you're applying for Non O no background check or insurance needed
Do you know if you took the time to read the requirements, you would not be in a state of confusion. So much accurate information out there. It would truly make your life easier to research. I say this with the utmost of respect.
In retirement, time one has. Unless you feel the need to buy large plots of land in someone else's name and become a farmer in your old age. Like I have seen so many times before. Agents work for some people , and some people like the challenges of doing things themselves. People do as they please.
On the site I had options for Stay with Friend and hotel where I stayed one night. I filled in both. At that stage I didn't have a fight but I entered the airline and flight number. No proof was asked for.
like Graham Seal wrote Go it immigration and get their list of requirements and do it yourself. 1900 baht later, you'll walk out with a sense of achievement. It's really not that hard. I once remember reading a post which said, even a caveman could do it.