I think your families did not come from a coastline, no? The great-great-whatever-great-parents of mine who were born in ports >1000km from each other weren't

I think your families did not come from a coastline, no? The great-great-whatever-great-parents of mine who were born in ports >1000km from each other weren't considered unusual, and certainly expected to stay in touch with both families. There was trade and boat traffic all the time.