I've not been to DPS although its relatively near for me, ma'am does that run once a month at least. I think KUL & SIN has the most connection to DPS, but would waste you quite a few hours compared to direct from ICN, seems like CX does only 1-2 flights per week. I would suggest ICN unless load is bad, in which case, I would suggest CX to KUL (3-4 flights a day) then LCC(or MH if you can) to DPS. LCC via KUL is a pain thou as the terminals are at different ends of the runway with no proper connectivity. Agree with mrs767er that you should avoid oz. My guess with LCC (using airasia) would prob cost you around US$80 1 way (after including surcharge for check-in bag, credit card for online booking, etc ,etc, not sure if they charge for seat belts)

As usual, avoid the major holidays, chinese new year, easter, summer & winter school holidays, christmas etc.

I think the weather there is sunny throughout the year.......