I used to do night freight in a Shed.
The biggest worry I can see is flying in winter if the a/c has no de-ice/anti-ice gear on it. It won't take long to ice up and that'll lead to all sorts of bother.
You should be able to get ~500kg of payload in it and ~2 hours worth of fuel. Whether or not this will be enough is another question.
I used to fly the C206 and C207 in the outback of Australia. (No ice to worry about)