A couple of points to clear up...
1. It was an instruction from my wife that she WILL be attending this wedding....even if flying Broome to Brissy and back was necessary...(close niece)
2. It was an instruction from my wife that she WILL be attending the wedding
3. It was an instruction from my wife that she WILL be attending the wedding
So with that out of the way, based on the dates of the Kimberlies trip, and the way we were heading home, there weren't going to be any viable airports that I could fly her to Brissy and then back to continue the journey... Alice Springs would be way too early, and Charleville is the next airport on our route, but that's only a 1 day drive from Brissy.
So I was thinking of looking to drive the Broome to Brissy via my above route, in 28 -30 days. Which gets us home in time for the wedding.
My plan B would be, if issues arose, or we are having too much fun, divert down to Adelaide, fly her home for the wedding and then back again, and then continue.
Hence my question was really about the viability of Broome to Brissy, via the described route, in 28-30 days.
Mark