Dear everybody,
thanks so much for the very helpful input! IŽll have to ask a friend in SIN to check with Jetstar wheter it is possible to book a SIN-PNH-REP-SIN itinerary, otherwise we would loose one day, as Jetstar has no flights SIN-REP on the day weŽd like to start the trip.
If the SIN-PNH-REP-SIN itinerary works out, the plan looks pretty much like this:
Day 1 SIN-PNH flight
Day 2-3 PHN sightseeing
Day 4 PNH-REP flight
Day 5-9 REP sightseeing with a sidetrip to Battambang
Day 10 REP-SIN flight
Once again thanks for the valuable input!