I am just kicking around ideas. A great settling for a story, or a series of stories would be a merchant starship. Long periods of just the main characters. A chance to pull into a new port from time to time.

But in a standard Star Wars/Star Trek sort of universe, what could possibly justify the cost of shipping something for a couple of months on the Kessel Run?

All systems have all the basic elements, none has anything special. Some biology might be worth transport.... once. After you get a dozen breeding pairs of cats to Llevuter-6 do you really need more?