If properties such as timelessness or an infinite past are inconceivable when applied to the universe, how does ascribing them to a creator make them any more conceivable?
Because the creator has magic powers and the universe does not.
Any objections you have to a universe with an infinite past, or a universe appearing from nothing, can be applied just as well to a creator simply by substituting the word "creator" for the word "universe".
Unless you consider the creator a god with supernatural powers, then its different from the universe and could have properties that the universe could not.
In fact, given the past fifty years, it's a safe bet that within most of our lifetimes something very counerintuitive will be discovered about how the universe works.
Yep, and they're fun to read about too.