Note that although Jet fuel is available at Buru Island airport, the availability of aviation gasoline on Buru Island is around ZERO
phil170258, I honestly think that 99% reading your book, including pilots who don't fly in that area, would never be aware of the above. Therefore, I strongly suggest that the Beech 18 is the best candidate for your cowboy operator/workhorse spec. Be sure to include an image or silhouette of the Beech 18 on the cover!
Good luck.