As the big question of having a litter box goes.
Our cat is trained to go to her private restroom, turn on the light and exhaust fan as needed. Ok, actually when she opens the "pet door" to her litter box located in the storage compartment, a magnet, attached to the swinging door signals a circuit to activate the light and fan for 20 minutes. All odors do go out the bottom of the RV. Often, Shadeaux the cat, will tap the door just to see the light come on..... sort of commanding "let there be light!"
Sometimes, "Boudreaux the diva dog" and Shadeaux will race around the coach until Shadeaux ducks into her restroom watching Mr. B come to a screeching halt with a look of "I ain't sticking my nose in there!"
PS. I get questions about the need for a light? Answer: She does like to read magazines while taking care of business.
Cheers