There are a lot of things that when mixed with a toddler are a recipe for disaster, but a litter box has got to be right on up there as one of the worst. I don't know what the rest of the world is doing with indoor cats and little kids, but despite all my searching, I could not find a good option.
When my daughter was first starting to walk, it became clear that our baby-gated-area was getting smaller and smaller and she needed more space to exercise her new found skill. But I was at a loss for what to do with my litter box. My house isn't huge, it's less than 2,000 square feet. We already utilize each of the bedrooms and I don't have a little awkward corner to gate off either. On top of that, I have super lazy cats. I didn't want to make their litter box a challenge to get to and wake up in the morning to a smelly present of defiance.
I did have a coat closet. Some people cut those little cat holes into their door and problem solved. Cat can get in, but toddler cannot. The idea is spot on, but the execution is lacking in my mind. I personally do not want a permanent hole in the door. It's not a temporary solution, it's a permanent solution. I don't plan on living in my same house forever, so I would have to either buy a new door eventually, or sell specifically to someone who had cats and no need of a coat closet. Not the greatest odds... and renters certainly couldn't get away with cutting a hole in their door. So I continued my search.
I still liked the idea of a cat being able to get in the door, but having the space be too small for a toddler to get in. I finally found my holy grail. The "Door Buddy."
This thing is kind of expensive for what it is. Someone could probably DIY a cheap and just as effective solution. But with the little time I have, I have no intention of spending it jimmying up this du-la-ma-hickey. There is an adjustable strap that keeps you from opening the door any further than it reaches, and a foam bumper to keep the door from closing.
I used the foam bumper on the top of my door to keep it basically the same position all the time. The strap is taut and can't open any more and the bumper is wedged in and can't close any tighter. It's not the prettiest thing I've ever seen, but it gets the job done with zero damage and very little work. I installed it in about five minutes. To me, that's a win.