Sneaking onto a planet at TL 10

[ArcLocke]

This discussion just puts me in mind of the "Trash" episode of Firefly. In the opening scene, Mal meets an old army buddy on a less-populated planet where they exchange goods they're working together to smuggle. It would take some work, but if the smugglers are taking part in these "relay runs," it's just a matter of working with a legitimate on-planet front to sell their goods on legal markets.

It is kind of the social engineering method you were trying to avoid, but with the limitations you've put on interplanetary travel, it's going to be difficult to come up with some kind of technological answer that won't be countered by planetary LEOs. In a high-tech setting, low-tech solutions are sometimes the easiest to work out.

A positive side-effect of running it this way is that you can have story hooks involving the Smugglers Guild: different crews are fighting over high-paying contracts, the fences are being rounded up by the law, the cargo your crew just picked up is a lot more dangerous than they were told, etc.