Added detail: the holes are slightly oversized.
Thanks for all the very useful and informative posts!
Glob some joint compound in and around the gap , apply paper joint tape over
gap going about an inch past each side of gap , hold one edge and wipe tight
, hold other edge and wipe tight , let dry , skim joint compound over tape ,
sand and skim again with joint compound , let dry , sand and touch up
paint...With setting type joint compound it can be done in one day...Good