I came last year for a month and used an agent to open an account. Returned to US and deposited/transferred the prerequisite 800k in the account. Returned 2 months later after it was "seasoned" Then used an agent to apply for my Retirement visa. Took a month for Immigration approval. In the meantime I used an agent to get my driver's license - had IDP so only had to take color and reaction test. Make sure you have both motorcycle and auto on IDP.
No direct flights from US. Vancouver I believe the only North American City that has a direct flight. The flights go through Different countries depending on Airline. For me I always check flight times. Depending on the Airline between 25-35+ hours.
Delta Partners with Korean Air and go thru Seoul. Others use Tokyo, Dubai, and others.
A retirement visa obtained here does not require health insurance Non-O visa. A retirement visa obtained from outside Thailand (O-A I believe requires Health Insurance, medical clearance and police check I believe is the current requirement). I used an agent & opened up a Thai Bank account. Transferred the 800k from my US account & waited for it to season 2 months. Then used an agent to apply for retirement visa