I would be angry at Romney in Justice, Defense, Interior, or many other positions. I’d be disappointed in Romney at State, but political beliefs are less important for Secretary of State than for most positions. As long as he’s not as eager to use the military as Hillary was, it won’t be terrible.
I’d make Romney Ambassador to Mexico.
Romney could be Secretary in charge of dismantling Obamacare, since he is the father of O’care, and thus is best qualified to get rid of it.