Does she need to get some preclearance or stamp or anything from Cambodian officials first (someone told me she did , but they did not know who where or how)?

Not sure if she is traveling by air or poipet land border.

If she is taking her three children, all included in her passport, any complications? Might be doing visa exempt for 14 days, would she need a plane ticket back (usual way for legal Khmers to travel is bus and minivan, not air)? If she gets a formal 30 day visa, would she need one for each of her three children?

If anyone knows a visa consultancy firm is siem reap or even Bangkok or Phnom Penh that would be appreciated, even better would be answers in this thread. Thank you very much.

T

Not sure about any clearance being needed.before departing but I don't recall reading anything about it.

At a border crossing they normally would not ask for a flight out but they may ask for to see 10k baht. By air a return or onward ticket would be needed.

A tourist visa from the embassy would allow an entry of 60 days. The children would also need visas.