I use my entire main floor as well. Kitchen and dining room for crafts and meals. Living area is the playroom and the younger ones nap in playpens in our bedrooms. Older ones no longer in playpens rest on the loveseats in the playroom.

Our family uses the basement as 'our' space. No daycare kiddos allowed down there. My son has a separate playroom down there too where he keeps any toys he does not want to share with the daycare.

I love the main floor lighting for the daycare, and I like to have a separate space downstairs so that we can get away from the toys/diapers/ etc that have invaded the main floor