S.F.
Hi,
We had the same problem, so we put the litter boxes in the basement and put a small cat door in the door to the basement. It is not necessarily a child proof cat door but my daughter cannot get through it. She has stuck her hand in there before but it is just soft plastic that swings back and forth so there is nothing for her hand to get stuck on. We bought it at petco in the dog section. The small dog door fits both of our cats just fine. There was an adjustment period for the cats, but they are both fine with it now. Hope this helps.