I've done a lot of thinking about what trade infrastructure would look like in the developed parts of the 3I. Basically, it looks a lot like modern container shipping. Economically significant systems will have a huge "port" area in deep space, well beyond the 100d jump limit, defined by orbital elements as much as by physical volume, and littered with various sorts of maintenance and cargo-handling facilities. Picture a really big container port, like the Port of Long Beach near where I live, but spread out in three dimensions over a huge volume. It wouldn't appear cluttered from inside it; space is big, Traveller makes in-system movement nearly free, and safety and navigation concerns would argue for very wide separation between operational nodes.
Fast long-haul shipping would be handled by modular freighters. The arriving ship would decouple from its freight and head off for refueling and maintenance. Meanwhile, a jump-ready modular freighter would couple with the freight and jump out. You could easily get the turnaround time to a couple of hours, most of that being taken up with moving the freighters around, docking, and doing safety checks to make sure the load is coupled properly before jumping.
Loads in-bound for the nearby world would just be left at an assigned spot in the port zone; lighters from the planet would then pick them up and downship them, and drop off outbound loads in other designated places.
The port control hub would probably be a very busy place, with truly impressive holographic displays to keep track of all of this.