elfouquer,
I flew air ambulance for 7 years. Perhaps my experience will help you decide...
My company had both rotor and fixed wing. Since you are looking at a King Air, I'll stick to the fixed wing side.
Fixed wing air ambulance is inter facility transport: from the patient's current hospital, to one with higher care. Mostly that means from a small town to a bigger city.
I have worked two schedules: 12 hours on, 12 off, 7 days on/7 off; and 24 hours, 20 days on/10 off. Both were on call with a response time of 20 minutes. That means 20 minutes to get to the plane, be ready to close doors, and turn engines. The 12/12 is more common, though the days on/off vary between companies.
The flying was challenging. Mostly night flights down, often to non-towered (or closed tower) airports. Only about half the places I flew had an ILS, and a few had no approaches. Occasionally, we flew to unimproved (turf or gravel) runways. The flight time was split evenly between 135 and 91. Every one of our PCs included a hand flown, single engine, non-precision (NDB if available), circle to land approach. 99% of it was single pilot. Flight time averaged about 200 hours PER YEAR.
The industry is often criticized for its safety record. Part of that is due to the type of flying done: crappy airports (or in the case of the helicopters, a wide spot in the road), in the middle of no where, with little wx information. I may get slammed for this, but too often it was the size of the pilot's b@lls that got him in trouble. Too big and he thought he could do anything, too small and he succumbed to the pressure of "If you don't fly, you're gonna kill this kid." (The most important thing for me was to remember I didn't make that kid sick, but a bad decision on my part COULD kill the kid, the nurses, and ME).
Good luck with whatever you choose,
j