Reading this as a European, it sounds like a lot could be learned by looking at Europe. Large container ships mostly stop at the north sea harbours (Rotterdam, Antwerpen, Bremerhaven, Hamburg, ...). Then, containers for the baltic ports are put on smaller feeder vessels, which go there. Or on river ships, if the destination is inland from the harbour. Heck, the baltic feeder ships aren't larger than those on the great lakes.
The same concept should work in North America, if it weren't for legal obstacles.
>>1990913> marine traffic carrying containers would have to pay a duty at both the Canadian port of handling, and the US port of arrival, so short-hop shipping is priced-out. There was the concept of the freeport. Basically, the border for customs purposes is not the quay, but the border of the harbour area. Putting stuff on a different ship in the same harbour (to bring it onwards to a different country) does not cause any duties to be paid.