The Chieftain, if we went that way, would be for longer regular (not RPT) Darwin runs but the Baron would be for work closer to home w/- 150nm
The Baron will get you and your passengers a lot further and faster than a dirty old Chieftain. With a load on the Chieftain will get you 165 minutes with full mains including reserves.
My only recommendation, and you can take this or leave it, is to forget the baron (far too expensive for what you get), and look into something along the lines of a P68 Partenavia.
Much better value for the same no. of bumbs on seats.
If this were the case there would be a lot of P68's in the charter realms.
A P68 is good for 135 knots, noisy as all hell and with max endurance will get 3 pax on board. A Baron will do 180 knots and carry 4 with max fuel a hell of a lot further.
300/hr to operate the bonanza?
Why Bother when you can hire a 182/mooney for ~250/hour, or a brand new 172 (with G1000) for ~ 180/hour??
It's ready when you want it at a moments notice which gives you flexibility. It's faster and can carry a greater load than a M201/C182 at a greater TAS.
Its like comparing a Hyandai to a Rolls Royce. It doesn't feel the same, sound the same, or give you the same satisfaction as a 520 spluttering to life then some time later at full song down a runway bound for the heavens.