Thanks to help from people on this site I was able to get my letter from the American Embassy in BBK by e-mail in a matter of hours. I went to Jomtien immigration this morning (6 am and was 7th in line) and by the time the doors opened there was a looong line but I was out by 9am with a 30 day extension to my "visa exemption". One interesting fact is that the the lady who checked my paperwork told me to keep my letter in case I needed another extension. Now, waiting to see if my JAL flight on Monday to Tokyo is a "go" or if it canceled like my Cathay Pacific flight. Again, thank you to the people who freely gave me help. This a very useful site!
TLDR : Answer Summary
The author successfully obtained a 30-day extension for their visa exemption in Thailand after receiving a helpful letter from the American Embassy. They visited Jomtien immigration early in the morning and encountered a long line but completed the process by 9 am. A commenter provided insights about the need (or lack thereof) for a letter for the first extension, and others discussed concerns about health risks at crowded venues.