The Imperial Fringe was published in 1981 as an "introductory adventure" included with the Deluxe Traveller boxed set. I acquired it on the "Classic Traveller" CD from Far Future Enterprises, which makes it a little hard to evaluate its value for money.
Calling The Imperial Fringe an adventure is somewhat misleading. It is actually the sketch of an enormous, sector-spanning, 20-year campaign. It is also, however, brilliant documentation on the designer's expectations about how a Traveller campaign might be run. I wish I had read this like 10 years ago when I was first getting started with Mongoose Traveller.
The pitch, basically, is that a senior member of the Scout Service contracts the players to do a survey of the sector and provide up-to-date UPP codes, based on in-person observations, of each of the 440 planets in the sector, with a time limit of 20 in-game years (1040 weeks). Reminder: a subsector map is 8x10 hexes and usually about 30-40 planets, and a sector is 16 such subsectors.
This sounds extraordinarily ambitious to someone coming from Mongoose 1e - our games have usually been confined to single subsectors and maybe two years of game-time. Occasionally a plot point would take us a little bit off of the edge of the subsector but the assumption was that this was a temporary state of affairs and that we shouldn't expect additional subsectors of prep effort.
The players get paid a fixed sum per world surveyed on submitting survey reports at Scout Service offices. This sets up a brilliant incentive to actually travel - you don't get paid for visiting the same planet a second time. And this leans into something I've liked about Traveller, which is that "planet of the week" allows a lot of variety. One week you can do Alien on a derelict, the next week you can do Blade Runner in the big city, the week after that you can do Mad Max stranded on a desert planet looking for water to run the reactor on, all with the same set of characters, without breaking continuity or suspension of disbelief, while continuing to build campaign capital.
I also really appreciate that this setup shows rather than tells you a lot about the Third Imperium. It is so huge, and travel so slow, that they do the census basically every 20 years, and official records about the state of whole planets can fall completely out of date in that time. And their solution to this problem is contracting the census out to a handful of retirees on a shoestring budget and a deadline measured in decades. The implications about the state capacity of the Imperium mark it as a very different situation from ours. Imperial subjects probably aren't filing individual tax returns with the central Imperial Revenue Service every year. The empire can just lose track of millions of people for decades. What does the response time of Imperial law enforcement look like? Weeks, months? If your ship gets "pulled over" by the Navy and they want to "run your plates", how out of date is that particular patrol cruiser's database of ship registrations? Is there even a standard Imperial-issue identification document like a passport? So it raises lots of fun questions.
Returning to gamier matters, The Imperial Fringe also makes explicit:
The assumption in the adventure is that one character has possession of a type S Scout/Courier and thus provides transportation for the group. The referee should suggest that one player attempt a scout career. If, after all character generation has been performed, no scout has a scout ship, one of them should be arbitrarily given a scout ship in order to further the adventure.
Obviously, I'm not thrilled at the suggestion to respect neither the oracular power of the chargen dice rolls nor the consequences of the risk/reward decisions of the players during chargen. But it is interesting to see that even this early, the official Word of Miller was "give 'em a ship," at least for introductory campaigns. And with a campaign of this scale, I have to wonder how many people started "introductory" campaigns and then ended up playing it for years of real-time.
Giving a known ship makes setting up appropriate rewards a lot more viable, plannable; if you know what their monthly ship costs are, and you know the rate at which they can survey, then you can set the pay structure up to keep them under light monetary tension, without it spiraling either down into overwhelming debt and desperation, nor up into huge piles of cash. And this makes sense in the world; your patron also knows what it costs to run a Scout/Courier and wants to encourage you to actually get the job done, rather than either failing due to lack of funds or retiring due to excess of funds before finishing.
The combination of the known-small cargo hold of the Scout/Courier and the strong incentive to keep moving on to new systems to write fresh survey reports probably constitutes a workable solution to the Golden Pair problem (though not a very general solution). It doesn't matter if there are two planets with strongly-complementary trade codes next door to each other; you barely have the means to exploit this opportunity on any single transit between them, and you have strong incentives to not do anything in a loop.
And while the initial setup procedure may not be maximally respectful of player agency, once the game has started they're just let loose upon the sector. No further railroads here...
Until you start inserting other published CT adventures into suggested systems, per page 19; then you might run into some small-scale railroads. I salute the hustle of using the introductory adventure to advertise the rest of the product line. But still, even if you do go buy all of those adventures and drop them into the sector map, you still have a big sandbox with a couple more-detailed points of interest rather than an adventure path like The Traveller Adventure, which came out a year later in 1982.
This suggestion to drop in modules throughout the sector does highlight one obvious weakness here, which is that there are a lot of worlds described with UPPs and no further details, and this is very much not a ready-to-use, "grab-and-go with no prep" kind of product. Significant Assembly Required to make each world interesting, to keep the game from turning into a "we jump, we descend, we check the survey boxes, we take off, we jump..." routine. Religious observance of the random encounter rules is probably wise, but not mentioned here; it might be easy for a new Traveller GM to miss. Maybe at the time knowledge of their use was more assumed, from old-school D&D?
The other difficulty that I have with The Imperial Fringe is a less universal one - it probably doesn't handle open-table play particularly well. You're going places well away from the main routes, so justifying characters appearing and disappearing out in the boonies strains disbelief a bit. And the ship doesn't have enough stateroom capacity to justify a "you're carrying everyone but half the crew has food poisoning this week" approach. A bigger ship with more space and enough crew for PCs to fade into and out of the background might be a way to do it though; basically a Star Trek-style "survey cruiser" sort of thing. But then you start having to think about command structures and payroll...
So yeah, I wish I'd read this back when I had a stable set of players in college, rather than adults with lives doing master's degrees while working full time jobs and raising kids and taking long vacations.