Also, for a big remote trip, a very decent First Aid Kit, and knowledge of how to use it. As someone who has been in situations where a PLB has had to be set off, you need to be prepared to sit tight and stablise any medical issues until paramedics can arrive, e.g if you're in the Blue Mountains and need a helicopter assistance (my background is in remote rope access activities) it can be at least 30-40 minutes before a Rescue Chopper gets into the area from Sydney, and then they have to try and pinpoint you.
If you ever set one off, do not move at all from it, and especially stay with the car, it's much easier for flight crew to recognise from the air then an individual person.
Same applies for crashes in terms of First Aid kits, having been first on the scene to a number of narly crashes, a decent first aid kit is vital to prevent bleeding and to treat other injuries until paramedics can arrive. And if you're travelling alot, it's only a matter of when, not if, you come across a crash.