Awesome Machine..Everyday we fly twotters at 4500' elev and isa +15 at max all up and the take off run with Flaps 10 is about 400-500m. We use 40PSI torque to stay within torque limits. with Flaps 20 it will be airborne in about 300m at those conditions. At Sea level with isa where you can use 50PSI at max with flaps 10 it will be airborne in about 300m, and with flaps 20 in <100m. These are not book figures just personal experience at sea level but with ISA +10.
Landing with full flap at max all up and braking you could pull it up in 200m..
An empty twotter touching down at <60kts we've stopped in less than 50m to avoid wildebeast crossing and ive taken off in about 30m at sea level fairly light ( well less than one and a half centre lines on the rwy).
As for operating costs its alright up to 200nm. It tends to get expensive after that unless its a runway that only the twotter can get in and out of.
Our company is looking at the B1900C for a 230nm route and the operating costs are similar on the book figures.
Why dont you go for a Caravan. Its a money maker, rugged, and also good short field performance.