I don't know how much experience comes into this. It is very much decision making process. Compared to many people on this forum I do not have a lot of Piloting experience, as pre 2005 most of my flying experience was as a mil and civil aircrewman.
I don't wish to critisize the Pilot at all. I wonder whether the aircraft was intentionaly decended to 1500ft at 12 nm or was the aircraft simply unable to maintain altitude even this far out.
This would be something I imagine you would want to find out early so you ca make an immediate decision. Something like; if your aircraft is not maintaining altitude below 5000ft then an immediate landing is the way to go. If it is then stay high and proceed home, decending over the field. This gives you more options if the good engine quits.
It is such a horrible situation. There are many suitable areas to put down in an emergency in NW Sydney: YSRI, M7, Schofields, open areas of land with no powerlines. It is better to have a broken aircraft and no job than to risk dying.
For some of you more experienced PA-31 pilots out there, if you had to put down on a road (other than a motorway) would it be wheels up or down?