This appears to be a picnic around the site of today's Fashion Valley Shopping Center.  I believe the photo looks southeast, with the Carmelite Monastery perched on the hill at the left rear.  My guess is that the white fence at the left is the old Kenmore Stables.  Westgate Park was the home of the Pacific Coast League Padres baseball team east of this site from 1958 to 1967.  That's a 1959 Ford on the right.