system
Given the following post, respond as if you're commenting on Reddit:
human
[star wars] billions of years after the original trilogy, if the technology in the star wars universe went far enough does the milky way exist in star wars, and could someone travel to it?
gpt
Well for starters the Milky Way DOES exist, its just far, far away from the GFFA.

Now as for your question, it is technically theoretically possible to travel from the GFFA to the Milky Way. In fact, there is limited extra galactic travel already in the world of Star Wars. The Rishi Maze is an irregular dwarf galaxy locked to the main galaxy. It is where Kamino was located and can be seen in the ending of ESB. 

Now as for traveling to other major galaxies, like mentioned, it is theoretically possible but there are some caveats.

Galaxies are orders of magnitude further apart than stars, and while Hyperspace "shortens" the distance it would still take a massive amount of time and energy. A ship would have to be able to carry enough supplies, especially enough Coaxium, to keep the Hyperdrives working. It would be a very difficult and expensive endeavor, but again, technically possible.

The second, and more salient point is that a Hyperspace route would need to have been plotted ahead of time. You can't just aim a ship at a direction and jump into Hyperspace,  well you can, but as Han so elegantly pointed out, that is how you crash into something and die. A route with jump points and coordination with obstacles and disturbances, all which are in motion, needs to exist to travel safely. In the past, this was done by explorers who made micro jumps, recorded data, compiled them, and essentially made maps. A very time consuming, expensive, and dangerous endeavor.

It could theoretically be done between galaxies, but the thing is no one knows just what is in between. There are ribbons of dark matter, energy, and who knows what else. All of that would have to be mapped, and it would take eons upon eons of time. Again, theoretically possible but crazy difficult and expensive to do. It wouldn't be the work of a generation, entire civilizations would rise, fall, others rise in their place, only to rise and fall themselves in a countless series before the work could be done, making it very hard to fund such an endeavor.

There is also one final point. Legend has it that there is a Hyperspace disturbance that surrounds the galaxy, maybe all galaxies, making it nearly impossible to cross the threshold. The Rishi Maze is essentially a satellite of the GFFA that the disturbances have all but disappated between the two, but who knows with any other galaxy. If one is even able to leave the GFFA, there is no guarantee that one could find their way into another.