In New Cannan, two kitchens = two dwellings, with some exceptions, such as homes with lovely guest cottages or pool houses and a few with the accessory apartment grandfathered on the property. New Canaan town codes are available on line. A couple of places are popping into my mind, but since I do not know your price point it is too soon to suggest. If you are NOT currently under a written agreement with another Realtor, I would be happy to help you and personally preview until I find THE ONE for mom & daughter! I can be reached 24/7 on my cell at 203-218-6664 or by email email@example.com.
By the way if other towns besides New Canaan, would be of interest, I know of a great deal more listings with accessory apartments.
Realtor Lisa Jones, GREEN, CIPS, ICREA
Golden Key Achiever with over $35,000,000 in recent sales