I checked old city directories from the 1960s and 1970s and found no listing for William Morrow. That doesn't mean that he didn't live in the area, only that he didn't live in town. It's possible that either a local library or the Idaho Historical Library might have an old telephone directory with a listing, and that might help narrow the cemeteries to search. Family trees on Ancestry indicate William's parents, Charles and Hazel, died 7 Jun 1978 and 2 Apr 1987 respectively. If you haven't already obtained their obituaries, they may yield some information. Good luck.