Days 1& 2 - Massive declutter. Post on Ebay/Vinted/Freecycle anything I think might sell or be wanted locally. Take the rest to charity shops or the tip, same day. (This might not take everyone 2 days but it would me. Include sheds, garage, attic, car, handbag, make-up bag etc. If there's time left over, use it for minor DIY jobs - tightening screws, regluing loose chair legs, hanging a painting, regrouting etc.
Day 3 - deep clean the house. Take duvets, curtains etc to laundrette with big machines for service wash and dry. Buy stocks of things like lightbulbs that fit your fittings (including for the extractor hood of the stove etc) fuses, medical kit etc so you always have what you actually need to hand.
Day 4 - sort out paperwork - make sure all bills and subs are up to date including any clubs/school trips for DC. Set up online grocery shopping list for basics on a fortnightly delivery plan. Transfer savings into highest interest accounts with reliable banks, switch utilities providers to best rates with reliable firms. Book medical check ups. Get up to date with email and cancel any subs you don't need or want.
Day 5 - in advance book hair and dental appointments, and brows/facial/nails if wanted or needed. Book fun - meet ups with friends, holiday reservations, theatre or gig tickets etc, so there's something to look forward to at least once a month for the next six months.
Day 6 - mega wash loads and batch book. Make meal plan for a six week rota. Always include 2 nights a week which are very easy or freezer based, so that if plans go pear shaped, these can be moved around.
Day 7 - rest. Plan a day out of the house so it stays clean and tidy, meeting up with friends or visiting somewhere you have always wanted to go. When you get back, lay out outfits for the week ahead for you and DC, including sports and swim kits in correct bags.