@khmen - thanx, very useful tips esp. abt the train during weekends only. Will have to consider that when planning.
@croc - will consider Koh Rong, maybe just a day trip from Snooky, though. I might travel in April (holy week) or May, depends on several factors. Btw, did your brother go diving in Puerto Galera last xmas break?
As of now, I'm partial to either Snooky in Cambo or Vung Tau in Vn, due to accessiblity by public transport. But nothing is final yet, so keep those suggestions coming...thnx all!