The Dash & Braz are great aircraft for these routes (Apu’s in summer
Just in regards to that APU thing. I recently did the mail run from Brisbane out to a far Western QLD port on the Rex SAAB. Fearing how hot it'd be given no APU (40+ degree days), I was pleasantly surprised at how cool they managed to keep it on the turnarounds when they shut down (some single engine turnarounds where possible). Air conditioning carts were plugged in when able and the crew made sure all blinds were closed to keep the direct sunlight out during a turnaround. So don't fear the whole no APU thing!
morno