I just wanted to thank all the helpful commenters on this list. I keep learning helpful things. Thank you each for both the questions you have asked and the responses that have been given
I am in a similar boat with a 90 day visa. I will be three days over when I leave Thailand due to a miscalculation on my part. M y Thai wife called immigration and they told her that it was no big deal. That when I go to the airport I would be sent to the immigration office and charged five hundred baht per each day over with no negative long term repercussions when I return later in the year with for another 90 day stay (using better math of course the next time 555.) They explained that, in my circumstance, paying a three day fine of 1500 baht was less money that going through what it would take to renew for another 90 days as far as hassle and the cost of renewal and said I should just renew before coming back.
I brought the woman who is my wife to the US. We took time building an in person relationship over 5 years as I traveled back and forth. We then had a traditional Thai Buddhist marriage, but did not register marriage in Thailand. This was followed three months later by our US marriage. To get her to the US I hired a US born atty living in BKK and applied for a fiance visa. Took about a year to get done I chose the fiance visa because I wanted her to have a three months in the US to decide if she wanted to stay before having a formal US wedding and working to change her over to a marriage visa and get her a green card. We are now married over 10 years, of course with ups and downs due to cultural differences. I should also say she was about fifty and I was 55 when we met.
There are many sites on the internet that look at these variables at various monthly budget figures. Suggest you do some research there to get answers that will best match your individual budget and personal priorities.
I just went through getting a marriage visa through the online portal. I have a state pension from Oregon. All I had to do was go to my portal on the state pension website and they had a statement much like my bank statement indicating what payments they have made and when. It was available for download as a pdf. So you might check to see if your state pension office has such a portal.