I’ve got a 19 and travel with 2 cats. I use a top opening Clevercat litter box and leave it on the floor on the drivers side next to the bed. (I sleep with my head on the passenger side and this doesn’t affect my getting into and out of the bed). The reason for this position is that the older cat has trouble jumping up to the bed and this makes it easier for her. Both cats are indoor only and think that the trailer is just another room in the house! I always close the hard door when I’m not in the trailer for fear that an aggressive dog might go through the screen to attack them.
Thanks to the interstate highway system, it is now possible to travel across the country from coast to coast without seeing anything - Charles Kuralt