It makes absolutely no sense to me why the shop owners have or require a random assortment of cloth, rum and plants, it makes more sense for the Cargo NPCs on islands but still think they need work rather than just standing there. I think it should be more specific.
Instead of getting rum bottles from the toolsmith surely every bit of cargo should be obtainable by the merchants or the most logical source; rum from taverns, cloth from clothing shop etc
Rum bottles delivered to an outpost should go to the tavern, cloth to the clothing shop, plants to the tavern or the merchants.
With more specific locations it could make sense to add new cargo too, crates of paper, wood that can't be used in repairs, metals for the weapons moth all of which would have their own specific traits of keep wet/dry.
Oh and any cargo run delivered to Grog Soaked Ed at Shipwreck Bay should be all rum, he's not buying new clothes and there plenty of plant life around him.