What do you think would be a good name for this perk? (It definitely won't be called "Marauding".)
The point is that supply is essentially what people usually spend their time on in such situations. Distribute goods among the caravans, distribute food from the caravans to the ships, and assign everyone to their places, etc. I think we should think in this direction.
"Accelerated March" is also not bad, but it evokes associations with the march of golems.