Ahh great, thanks Todd. Are there any 'easier' immigration offices between Chiang Mai and Bangkok to do this? Perhaps Chiang Mai is easiest. I may start heading to BKK via Phitsanulok. Last time Chiang Mai was in and out without the need to return 14 days later - not sure if they are still that flexible.
ok, I'll give that a try. I didn't see how that would be unethical, if I genuinely book a room and sleep there on the day I go to immigration - this seems perfectly ok to me. The landlady here doesn't speak English, so it's tricky.