Forget the Twin Otter except on routes where it's STOL capabilities are essential, it is slow, fixed undercarriage, unpressuised, noisy and not a pleasant experience.
As for suggestions of a J41 but with a restricted load, great, paying Eiurocontrol, fuel, landing/navigation fees etc. for some 10+ seats that shall forever remain empty, not a good business plan if the objective is to make money.
The Do228 on the other hand, PDQ, pressurised and retractable gear.