> Everything else on board for propulsion and housing the pilot would be on the scale of a small prop aircraft

It's likely that any cargo airship would fly for days/weeks at a time and would require at least 4 crew-members and everything they would need for the length of the voyage. So less a small prop and more something akin to facilities available on a yacht/Large RV.

> You might not even need pilots since these would be perfect targets for automation.

This would perhaps be the best solution