Unfortunately I can't really trace the MacAndrews/McAndrews family back further for you but I can tell you about John King MacAndrew's brother, James MacAndrews, who is one of my ancestors.
James was born 25 October 1816 in Scotland, and died on April 17, 1883 in Nova Scotia. His wife was Isabel Craig (b. abt 1816 Scotland, d. bef 1853 Nova Scotia) and together they had 13 children(!): Sarah Eleuthet, George Elmer, Robert (b 20 Jan 1834 NS, d 2 Nov 1867 NS), Henry (b 23 Oct 1836 NS), William (b 13 Sep 1838 NS), Matilda (b 31 Aug 1840 NS), Donald (b 29 Sep 1842 NS, d 14 Nov 1849 NS), Mary Jane (13 Sep 1844 NS), John (b 1846 NS), Annie Ruth (b 29 Aug 1846 Port George NS, d 6 Jan 1915 Lynn MA, buried 9 Feb 1915 Pine Grove Cemetery Lynn - married James P. Foster** My Ancestor), Margaret (b 14 Sept 1848 NS), Isabel Liza (b 10 Aug 1850 NS, d 7 Jan 1853 NS), and Laleah (b 28 Sep 1842 NS, m. John Gullivan). Another clue which may help you is that in my file I had down that your John King MacAndrews was married to a lady by the name of Eleanor (I presume I got this from the census but I'm trying to remember now...) who was born abt 1829 in NS and died 30 Sept 1884 in Annapolis, NS.