If you can stomach the slow cruise speeds (sectors look short enough) and afford ANR for the pax (see below for a great 'review' of noise levels) a BN2 would be a good shout. Its got the payload, cheap operating costs and can get in and out of anything. Might even be able to afford a new one. Bear in mind turbine requires a type rating for whoever you get to fly it (piston doesn't).
http://www.pprune.org/tech-log/43631...-islander.html