From the roots צ.פ.ן ‘conceal, hide’ (literary; because the sun doesn’t pass through the north, or at least it’s ‘hidden’ when it’s there) and ד.ו.ר ‘reside’ (because the sun ‘resides’ in the south where it’s at peak height).
No, you cannot construe דָּרוֹם from דור. What became of the waw and where does the mem come from. But, yes, for צָפוֹן this is a possible, but debated, explanation.
אאא הספר המפורסם