Travelling REALLY Far From Home [AU]

Wrath of The Ancients gave us interstellar and ship teleportation, and the whole Ancients Trilogy gave us such wonders as pocket universes to play with.
Elsewhere, we have Deepnight Revelation, with its theme of an expedition heading Spinward / Rimward to the very edge of the galaxy
- and beyond the Milky Way, to one of the Magellanic could dwarf galaxies orbiting it
and the Zhodani Core Expeditions and Solomani Rimward Expeditions with all their mysteries.
There's a reshowing of an old TV series, Stargate Universe, on our local TV, and it's whetted an appetite for adventures taking place beyond the edge of Charted Space.
There is nothing really stopping a referee from introducing some true wonders into the game, set so far away as to more or less require a one way trip out of one's familiar worlds. I mean, we're talking about things like your Travellers finding themselves literally teleported thousands of parsecs away onto, well let's borrow from Stargate, an Ancient ship, equipped with wonders such as a space-folding Skip-6 drive, collectors, a Silver Globe, and weapons such as a solar pulse and a spinal "superlaser" or similar.
Want your Travellers to visit Anomaly One, or pass through Essaray space and trash that machine empire? Or perhaps drop by the Magellanic coulds and rescue the Deepnight Revelation cruiser and her crew? In an alternate universe, or one set in the OTU where the Travellers have gone through the Ancients trilogy and come out changed, there's nothing really stopping you.
At the very least, you can put the WBH and Sector Construction Guide to good use.
Already in process; I was working on something along these lines about the same time as Mongoose announced those works. The campaign I'm toying with was originally intended to be set around where the Spinner wound up being placed; with the publication of Rim Expeditions it has since been displaced completely beyond the Orion Spur, on or near to the Coreward border of the Perseus Arm.

Basic premise is one of the Solomani colonization efforts from before the Long Night suffered a very long-range misjump, ending up close to the edge of an open cluster on the near edge of the Perseus Arm, about two and a half kiloparsecs from home, about half of which is between-arms rift space... so, no easy way home. Bring this forward to contemporary times , and I've set up a human polity (among several non-human ones) but removed - and replaced - a lot of the Third Imperium politics. Hivers and Aslan are on the list of aliens to watch for (but they haven't been encountered), Zhodani, Vargr, Droyne, and Hivers are a more distant (and nearly mythical) possibility.

And to add to the potential fun, once the home cluster is somewhat explored, the easiest route back to mythical Olde Home Terra actually starts in the opposite direction, making a (relatively) short crossing to the Perseus Arm and then taking a long odyssey around the trans-arm rift and back towards Known Space. (Considering the distances involved, it may be simpler to research Skip technology...) All in all, I'm expecting the campaign to stay local, leaving a "Return Expedition" more in the hands of government or other high-level entities.
Did you see the latest about the Magellanic cloud dwarf galaxies?

Anyway, my take on the big picture.

1 - the first star-farers, there were cultures that evolved in our (and other) galaxies billions of years ago
2 - the whole of charted space is nothing more than an experiment
3 - there are cultures out there that have reality maniputlation technology

That last one is the key to galaxy spanning adventures while staying within "Traveller canon"

Teleportation TL 27 is the ability (using Reality Manipulation)
to move objects from one place to another.

Reality Drive TL 28. Drives capable of reaching almost
any destination with a minimum of cost and time.

So all you need is for your party of Travellers to stumble across a TL28+ go anywhere drive, I can think of dozens of scenarios about how this could happen. or it could be the Travellers are observers from one of the cultures that set up the charted space experiment and with the events of the Ancients trilogy and DNR they have to sort out the mess.
TL 28 Reality Drive would be fun. I'll have to get my hands on those rules. The Travellers' ship would be a coveted vehicle along the lines of the USS Discovery from that TV show.
Only, without the mushrooms.
So all you need is for your party of Travellers to stumble across a TL28+ go anywhere drive,
All I am seeing is the SEP field drive, powered by the simulation of an Italian Bistro.
Got a missile inbound? Engage the Somebody Else's Problem field. No more missile. Well, no missile HERE.