The problem Flywatch have is that they are trying to offer a competitive SEN-LTQ fare on a 6-seater Navajo and the ecomomics just don't add up unfortunately.
They would probably do better to cost the operation on the basis of the 9-seater Chieftain which they say they are planning to acquire for the route. Having 50% greater capacity they could offer a slightly lower basic fare but, more importantly, they could also offer promotional fares for part of the capacity - much as Skysouth and Lyddair already do. That would obviously mean operating initially close to breakeven at best with the Navajo, but it would be the best way of establishing whether or not the route is viable over the long run. They also need to have an online booking facility as soon as possible as, these days, customers don't expect to have to telephone an airline to make a booking.