I’ve got a dog that won’t knock stuff over unless he thinks he needs to. I can put a dining room chair in the walkway between the dining room and the living room and he won’t go through, even though he can easily get around the chair. Only time he’s done it was when a stranger knocked on the door that he didn’t like.
So anyways the cat box is in the utility room. We just slide a tall laundry basket in the way of the doorway and if the door’s open we and the cats can get in but he won’t go pass it because it’s not that important. Laundry basket isn’t there though and he’s in the utility room eating out of the cat box within 5 minutes.
Our dog is named Buster for a reason. Until he got sick, he was as unstoppable as a freight train. No obstacle too big or too small to plow through!