The line 'they left before daybreak on a buckskin and roan"....o'kay, Then I'm not sure, I'm no poet, but the next line, "Past tall shivering pines where mockingbirds moan." Perhaps this signifies a bad omen, I'm not sure. Then the next line almost could be taken as the couple have crossed into a spirit world destined to roam and eyes never see. "Past dark cloudy windows where eyes never see. Perhaps there is no reflection of them on the windows because they're not of this earth any longer, they're now unseen. It could be they're cursed to roam for their misdeeds. All quite ghostly, a warning. Or maybe it's just what it is and I'm reading into this too deeply, what say you all?