For those flying from Tasmania and regional cities in NSW, QLD, VIC you are likely to be flying to WA via Sydney, Melbourne or Brisbane.
One thing I would like to suggest is perhaps not trying these flights in one go. The direct flights to Broome from Sydney, Melbourne and Brisbane leave early/mid-morning. If you are flying in from a regional airport to catch this flight you may be looking at a very early departure from home and a tight connection between flights.
In theory the time between flights in Sydney or Melbourne of as little as 30 minutes is considered adequate for connection purposes. But my goodness that doesn’t leave much wriggle room for delays. Anyone who has ever caught a commercial flight in Australia knows that just because it is scheduled to take off at a certain time does not mean it actually will. I sometimes wonder if those airline staff who oversee these extremely tight flight connections have ever actually had to change planes in a large (and perhaps unfamiliar) airport.
Sure if you miss your connection in Melbourne or Sydney then Qantas will endeavour to get you to Broome somehow but it won’t be direct and it is a stressful way to start your holiday.
Both Sydney and Melbourne airports have (by Australian standards) reasonably priced hotels either walking distance from the terminal or a short shuttle ride away. So is it worth considering flying the night before and staying over in Sydney or Melbourne for the night. If the flight is booked all the way through to Broome then you probably don’t even need to collect your bags as they will be forwarded onto the connecting flight. So make sure you have a change of clothes and a toothbrush in your carry on bag and then you can make your way to your gate without stress.