Actually its not that hard.
For the most post it can be obtained within 6 to 9 months if the operator has the correct staff, manuals and attitude.
ASETPA is looked at in a similar way to RPT. You must have a CAR 217, your aircraft must be class A maintained and your organisation must be suitable to monitor all of the above. If you treat it just like an extension of charter you end up taking three or more years.... just ask an operator in the Kimberely.
I have been involved in two ASETPA set ups that have been processed in well under 12 months.
OCTA