It depends on how broadly you define the term government in the local context.
If the Khmer news sources are available online, then you don't need to be physically there to source them. Based on what I've seen of Cambodian, Burmese and other foreign workers in my country, they mainly access news from home online on their smartphones. One can make a Khmer friend or Khmer-speaking friend online and ask them to help or perhaps engage one of those online pay-per-hour freelancers who do blogging, reporting, research work, etc. Anyway, I'm not going to speculate or make further suggestions without elaboration from the OP as to what he's looking for (that is if he wishes to do so).As for accessing Khmer media, presumably written in Khmer ? Well, take the baht bus down to Jomtien, find a Cambodian who speaks good English & pay him.