Timely post. I will in PP soon and face the same problem: my home currency EUR, and I don't want to exchange EUR to THB to USD in Thailand, but rather do it in Cambodia to lose only once. I remember last time in PP (Aug 2016) near the bus station, only the third exchange booth I asked took my EUR! Small booth not connected to a bank or chain, but I needed the money now to pay for the bus ticket.
For one week in Cambodia I will need about 300 EUR, and nowadays ATMs charge 5 USD (and I don't know how unfavorable my bank's or visa exchange rate is), so I rather exchange cash. For Thailand, I scrupulously calculated that exchanging cash has the least losses EUR to THB.
http://christianpfc.blogspot.com/201...-exchange.html
As for the lost post, occasionally I have internet problems and when I press "post/send", my text disappears, or there is an error message, but fortunately somehow comes back when I post again (auto saved by forum software). To be safe, highlight and copy before sending or write longer posts in a text processing program.