If the universe is never ending, then wouldn't he still have to be working on the universe?
I believe God was responsible for the initial Big Bang and the set of physical rules that the universe obeys. The universe simply continues to follow those physical rules which we are learning more about each year.
That isn't to say He couldn't take a special interest in some star system or galaxy for some purpose, but direct action isn't required for it to keep expanding physically.
He has intervened in Earth's history and suspended physical laws from time to time. In fact, any time there is a miracle that happens or a healing, God has intervened in what the physical laws he established would have brought about. But unless He chooses to act for some specific reason, the universe will go on until He brings it to an end.
But also remember, that when we look into the night sky, what we see is a throwback in time. Light is incredibly fast, traveling around 299,792.458 km/s. But even at that speed, the distances involved are incredibly large. When we look at the sun in the sky, we see it as it looked 8.317 minutes ago. If we were on Pluto at its farthest distance from the sun, we would be seeing the sun as it looked 5.4667 hours or so ago. Our most powerful telescopes only see Pluto as it looked somewhere between 5.46 and 4.11 hours ago, depending on where Earth and Pluto are in their respective orbits. Even when a remote spacecraft takes a local picture, by the time we see it it is just as old because the spacecraft can't send data faster than light either.
We see the nearest stars in Alpha Centauri as they appeared 4.37 years ago. We see the most distant galaxies as they looked around 13 to 14 billion years ago. So you have to realize that much of the star formation that we see, or galactic collisions or near misses really happened a long time in the past. With the distances involved, we will never live long enough on Earth to see what God is doing anywhere else in the universe at this exact time. Granted that for relatively nearby spots, like Alpha Centauri, if we were looking at the right time and what He did right at this moment in time was really significant then we might see it in a few years. But the time-distance problem for most of the universe means that we won't see anything that happens immediately, or soon, or for most things in the lifetime of humanity through all our descendants generations assuming the rapture doesn't happen earlier, of course.