Since we also had dogs that enjoyed kitty pootreats, we needed to have a way to restrict access to the dogs but also give our 19 year old cat access. The lower shelf of one of the cupboards was at floor level and a litter box fit nicely info the corner. When we were on the road, the cupboard door was closed. When parked, the door was open enough to let kitty in but dogs out. Worked great!
Just lifted the litter box out to clean it. There was linoleum on the floor in the cupboard so cleaning was easy. Our fifth wheel has lots of storage area so I didn't miss having that cupboard area.