Those Caravans you see are operated on contract by companies such as Wiggins and Mountain Air Cargo for FedEx. They operate all over the place.
Generally, from what I've seen, mins are pretty high, I believe Wiggins wants somewhere around 2500 hrs (though I'm not positive of the exact #) I believe the high mins are due to the fact that the AC are very expensive turbine aircraft operated at night in all kinds of bad weather, single pilot. Also, they are operated under CFR135, requiring that the pilots at least meet the 135 IFR min qualifications.
In short, these are not beginner jobs, they look for experienced pilots.