Any form of FTL, including traversable wormholes, allows backwards time travel. (EDIT: I mean going backwards in coordinate time. We get to closed timelike curves later in the post.) My world has traversable wormholes, so I just bite the bullet and say yes, anyone with the ability to use wormholes can travel back in time as much as they like. For example, if you want to appear on the moon 1 second ago, you can set up wormholes to do that.
How do we deal with time travel paradoxes then? Well, there is one rule about how the wormholes work. You can't arrange them into closed timelike curves. The moon example is fine, because even though you can go to the moon 1 second ago, it takes you at least 1.28 seconds to get back to Earth, so you can't actually change your own past using them. In fact, most things we think of as time travel just don't work; time travel is only allowed because physics demand it, but we take away its ability for you to influence your own past.
What if you tried to make a wormhole that took you to the moon 2 seconds in the past? Well, if you tried to set up the wormholes to do that, the wormholes would just blow up. Quite violently in fact. All the wormholes are forced to obey the Chronology protection conjecture in my world. If you try to arrange wormholes close to violating it, enough wormholes will blow up that the violation is never reached (usually more). Quoting from that Wikipedia article:
Initial attempts to apply semiclassical gravity to the traversable wormhole time machine indicated that at exactly the moment that wormhole would first allow for closed timelike curves, quantum vacuum fluctuations build up and drive the energy density to infinity in the region of the wormholes.
Anyways, with those rules, humanity wants to take over the galaxy with these things, but without the wormholes blowing up. What is the most efficient solution to colonizing the galaxy with wormholes that obey Chronology protection?
- There are currently wormholes that can take you from Earth to Alpha Centauri, 4.2 light years in the future. The goal is to build wormholes from Alpha Centauri to every other solar system in the galaxy (the government does not want people building all of these wormholes from Earth for alleged safety reasons).
- Around Alpha Centauri, there is a machine that creates wormholes. At creation time, the mouths are created at almost the same point in spacetime, but after that can be separated and carried wherever. EDIT: The machine specifically can create Ellis wormholes (and Ellis drainholes).
- The spaceships that carry the wormholes are traditional chemical rockets. However, they can go at great speeds because fuel and other resources can be delivered through the same wormhole it is tasked to carry. Also keep in mind that this means the wormholes will be time dilated significantly. In fact, that is a good thing, because it allows you to use the wormhole before its completed!
- An end of one wormhole can traverse through another wormhole.
- The only real restriction on how they are placed is that if they are arranged in such a way that they would form a closed timelike curve, they violently explode instead. However, it is also preferable for efficiency reasons to place them in orbits around things (because then the machine only needs to stabilize the wormhole, not levitate it).
- Wormhole Inc. has access to the galaxy's finest time-dilated quantum super computers and are willing to spend years on mission planning, so you have time to find a solution. Cheaper and faster is better.
EDIT: The question is how Wormhole Inc. can most efficiently distribute wormholes according to these rules, not how to change the rules to better accommodate Wormhole Inc. (although that is itself an interesting question).