Funny thing is Bali is actually closer to Broome and Port Hedland than they are to Perth. Makes you realise how big W.A. is or how small the world really is.
Flight time from PD to Bali is 1hr 50min. If Broome had a full time permanent International Airport (may be happening soon with Silkair) than the flight from Broome to Bali would only be about 1hr 40min.
As Jose said, Skywest aircraft are non ETOPS and hence track via a position 15S 119E.
Cheers