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.