Buses or minivans between cities. Book through any of the numerous agents. You will be travelling with locals as well as other Westerners.
There are no passenger trains in Cambodia.
Tuk-tuk drivers are annoyingly pushy but generally more honest than in some nearby countries.
Cyclos (cycle rickshaws) are a fun and inexpensive way to get round Phnom Penh if you are not in any hurry.
‘VIP’ buses at a price which seems too good to be true. It is a scam.
Need to book in advance?
Advisable, but same day tickets can usually be sourced with patience.
Almost universally, often fluently. All signs and notices are bilingual (Khmer/English).