EESDL
Although the King Air is a single pilot aeroplane it's far better and safer to fly two crew (been there, bought the t-shirt, for both one and two crew operations).
Advantage of getting someone to operate it for you is that they can generally have crew available to cover for holidays, illnesses etc. plus have experience of running just the sort of flights you need. FW is quite different to RW.
Beware any operators that claim they can put lots of AOC hours on it and make a profit for you, think of forked-tongues. They all just love someone else to buy the aeroplane, pay the overheads then charter it out at low prices to undercut the opposition. In the process giving the owner little chance to fly it when he wants.
I'm sure Daifly can give you honest information (no I don't work for him!). But know exactly what YOU need and let that be the driving controller. How many pax, all the destinations (Le Mans is a bit short for a lot of AOC flights), whether your boss expects the aeroplane and crew to be waiting 24 hours a day at his behest, especially when at a race circuit. Do some homework to estimate just how many flights and hence hours per year, some costs for landing, handling, Eurocontrol charges, flight planning software, crew costs downline (food and beer!).
Going to an AOC operator can mean extra costs, aeroplane and crew working to JAR OPS 1, but if you get a good, professionally run outfit to help you then it will take all the strain, and maybe by letting them operate on charter, when YOU don't need the aeroplane, then some of the costs can be reduced. But the important thing is that YOU must keep total control of when and where the aeroplane operates for your benefit. Find out whether there are any advantages to having the aeroplane NOT on the G-reg.