Change the passport after you come back. That is by far the easiest approach.
She can always start changing the name change process this year, and moving over work, social security, etc. But I'd wait for the DL/passport.
We found after our honeymoon (which was immediately after the wedding) that the marriage license goes a long way in changing names, even months later. That's all that the state and federal governments need for the wife's name change. (That the husband's name change requires a court visit is an interesting tidbit).