The question is not how to develop a program that needs no planning time. The effectiveness of the school day is equal to the quality of planning provided. Each evening, an hour before the children's bedtime, the father could take over the exclusive supervision of the children. This can be a time to read aloud, conduct Bible class, or any area of instruction that you might like to teach. It is also a good time to play games, sing songs, tell stories, get out the family album, write letters to friends and missionaries, and similar activities.
Mother can go off and prepare lessons and activities for the next day.
Following the bedtime rituals, which both you and Mother will want to participate in, the evening is then free for additional preparation and a most desperately needed time for personal communication with each other. Any mother who has been exclusively with children all day, needs an adult to talk to. It is important to talk about the educational efforts, but you will be wise to reserve some of this time for maintaining and building a b personal relationship with her. In addition to the daily involvement with the family, the overall structure and planning of the home-education effort is your responsibility. This means involvement in studying curricular choices, setting goals, evaluating progress, determining schedules, planning breaks, and maintaining the delight and joy of the home environment.