Just a thought: it seems to be a recurring notion of the Pope having to flee Rome and take refuge somewhere in the Americas. I wouldn't get too wrapped up in this since 'across the sea' could mean Nome, Alaska or Tierra del Fuego- or Long Beach Island, New Jersey.
If I had to make a snap guess, the Great Monarch will be an American of French and German ancestry. We know that as a boy he will have been a great sinner but latter embraces the Faith and performs many penances. Clearly, he will be able to lead armies in strange areas.
Implicit in this is that he will be one of the few Catholics remaining loyal to the old rites and the spirit of the Faith as it always was. Probably, he is hidden from the world, more or less. And we can speculate from here.
The most important thing each of us can do is have a well-ordered Catholic life, remain in a state of grace, and know that for each of us the End might well come like a thief in the night.
As long as we are leading proper Catholic lives, which is not easy by any stretch, all things will order themselves.