'you out there, in the cold''me with my heartful of headlines' - the letters are not as deep as she would like as they are mainly to catch up on eachothers lives. headlines often exadurate. they live completely different lives despite their bond.
'clearing a path through snow' metaphorical of the emotional barrier being cleared so they can stay close. snow built up over time and now must be cleared.
'our souls tap out messages across the icy miles' - metaphor shows how they will not allow themselves to become disconnected.'our' shows that the connection is mutual as they both want to become closer. icy miles may show that the warmth of their relationship is enough to melt the ice.