My wife and I are trying to plan a trip to Asia using a Mileage Plus award, but we're having a little difficulty using our miles to get all the way to our desired destinations - places like Phuket and Bali. So we were thinking of just using our award to get to Singapore or Bangkok for free and then finding our own way on a discount airline.

I took a quick look, and it looks like flights from Singapore to Phuket and Bali are ridiculously cheap on Air Asia (I saw between $5 and $20), and I'm sure there are more discount airlines. Also, I should mention that we'd be traveling with a baby and most discount airlines seem to be stingy about baggage and weight limits. Also, should we be concerned about safety?

Is there any reason to struggle with mileage availability when discount airlines are so cheap?