Keep in mind the DTV is a glorified tourist visa. If you're setting up home on a tourist visa, expect to be bitten badly. Perhaps you need to look at more solid solutions
In CM most probably, but again, I'm talking about Bangkok. Perhaps a small concession as the immigration office is a long way out for such a minor task
What a strange comment! I simply offer advice which is factual. No opinion at all. 90-day reports in Bangkok are easily done by mail. I acknowledged maybe CM it's not possible. Why has that triggered you?
Before committing yourself to Chiang Mai, take a look around. Don't get too obsessed at having to buy somewhere to live - chances are you'll regret it long term. Rent for shorter terms in a few places. Keep in mind that Feb-March-April CM becomes the most polluted city on the planet. If you have any respiratory issues, you will suffer badly. If you don't have respiratory issues, you soon will. Just take your time and explore