On the third day - This indicates that Aphek was three days’ march from Ziklag, say about 50 miles, which agrees very well with the probable situation of Aphek (1 Samuel 4:1 note). From Ziklag to Shunem would not be less than 80 or 90 miles.
The Amalekites, in retaliation of David’s raids 1 Samuel 27:8-9, invaded “the south” of Judah Joshua 15:21; but owing to the absence of all the men with David there was no resistance, and consequently the women and children were carried off as prey, and uninjured.