A-Viator will do 200+ at half the cost of a kingy, less fuel than a 208 and still carry eight pax comfortably
Its still a Partenavia and service/parts back up is way behind a 208, let alone the capital cost.
The way I see it the 208 is the modern form of the 206/207. For a base in Mildura its 175 knots gets to all the likely destinations without refueling and has the enormous potential for charter, assuming the owner wants additional revenue.
With the intended loads suggested there is nothing else that will carry the required number of pax/load with required fuel and do it with turbine smoothness and efficiency.
Spending huge money on a 40 year old plane is stupid. The resale on a good well looked after 208 will ensure that the whole operation makes financial sense.
Nobody has suggested anything that will carry the fuel/load with similar efficiency for a similar investment compared to the 208