If you can avoid the bait-and-switch feeling with the players, sure.  Like starting a fantasy campaign and then the players find out they are living on a ringworld where civilization fell ages ago.  Or a fantasy world where it turns out everyone was just doing cosplay with really advanced tech and no one wanted to be the first to break character.

I agree with Earth not being on a standard type Nav cube.  However, are Nursery World Nav cubes a thing? 

Also, Earth astronomers can now check for signs of life (or at least the chemical composition of the atmosphere) with the transit spectroscopy method; so you could check a lot of planets fairly quickly.  Although line-of-sight and waiting for the planet to orbit in front of the star means you probably can't check every one of those 63 stars using transit spectroscopy.

Now before you complain, Richard confirmed this. Incursion is in the Bureau 13 universe. One piece of evidence is that one of the Focus Characters, Joanna Barnes was involved with the focus character from B13, to quote: "After ditching her boyfriend, a crazy Science Fiction writer who thought he worked for some secret governmental agency..." that is, Robert Harrison.

That means the supernatural is definitely a component to this universe. Now, unless your PCs are former agents for the Bureau or other similar Earth agencies, they probably won't notice the weirdness and attribute it to the place being an Alien world. But it does have implications.

So, Headcannon Time: The reason no one has been able to reproduce Anshani technology is that the Anshani did the thing most folks tell you not to do: Mix magic with technology. The White Boxes can't be reproduced because there's spells on them. The HFTL and the InterGalactic version of it? Magic and Technology.

Why were the Anshani the only ones to figure it out? Well, they weren't. Because they are big "P" pacifists, they didn't do the one thing every other species did when they tried to mix magic and tech: Make Weapons with it. Every other culture ended up smoking ruins because their first impulse was to make a BFG that shot Balrogs...

There are other implications about this. The Fae. The Land of the Fae is another radically different universe that intersects the Bureau's through various fairy rings, magic mirrors, portals, and the like. Elves are everywhere... but how they appear depends on the species and culture of each world. A Teb Elf would look nothing like the ones that bedevil Earth, but they could be the exact same person, just shifting their appearance for the different species.

And that means you could use the Land of the Fae as a way to get back to Earth, right?

Ummmmmm...

The Land of the Fae does not operate by any rules that humans or other species can discern. Time is optional in the land, as is distance, substance, and other features. Use the Land to go home could result in you returning thousands of years later... or earlier. The trip could take a lifetime, or a minute through the Land. And you may not be able to leave if you are incautious and partake of any meal or drink offered by the residents.

And that's assuming Oberon or someone just like them decides it's time for the Hunt and look... prey.

This of course presents an opportunity for a GM and willing players. WILLING PLAYERS. A Bureau team is sent out in a Bureau designed research sub to investigate that North Atlantic anomaly... only to get blipped across the galaxy to the shipyard where the sub is turned into a spaceship. "Oh woe is me!" they wail. "Oh wait, I have a Bureau Cell Phone. It always gets bars!" Phoning home is easy with Bureau technology... that mixes magic with tech... heyyyy....!

Thoughts?

So, I've have had many a "discussion" on this topic with various folks. We all disagree on one thing: Finding a Nav Cube with a destination for the Sol System.

Most folks think that there is one. I totally disagree.

Why? Because the Earth was a restricted Anshani world, a Nursery World. Why would a Space Tugboat, AKA the Ardanna Nuu, have a cube for that world? It wouldn't. But, it would have a cube for a Anshani administrative world, one that watched over many Nursery Worlds. Now, since stars move, the admin world would have a shifting area of responsibility, especially since the Anshani, a species over 8 billion years old, had more than enough patience to deal with the shifting stars as they travelled around the galaxy.

So, the admin world would be about 20-50 LY from the Sol System. That also means that there probably many other Nursery Worlds near Earth as well. There are close to a thousand stars within 50 light years of Sol, enough that it would take a lifetime to find Sol and Earth. Even if you left it to just the type G stars that's 63 different stars to check out to see if they are a match. And using the constellations won't help much. At 50 LY, they would be unrecognizable. 

It would be the height of irony, if cube #1 was the one to get them home. It's the one that's sitting in the Nav controller as they were traveling. Which world? The first one, the Frozen planet with High Tech buildings. It's been a hundred thousand years since the Anshani threw up their hands and ascended/left the universe/whatever. It's amazing that it's still mostly intact. The fact that Dakkel Shumeh didn't tell them is that he's a bit of a schmuck. If they can hunt him down after leaving him somewhere, he might relent and let them know basically what direction Sol is from the Frozen planet.

Thoughts?

There is a cap.  Vyndanian managed to answer the Tri Tac questions I have been using to keep the scammers out and get himself registered as a Field Agent instead of a Rookie.  I think I've closed the loophole, but the permissions are sort of a mess.  I ported the forums to SMF from a different software that had glitched so badly it wouldn't save or upgrade, so the only other option was to lose everything and start over.  So I hand rebuilt them.

I have upgraded the forums and pruned a bunch of crap.  I think this should take care of the issues.