We full timed in a truck camper for 2 years with 2 cats. Issues were minimal. We had elevated perches on the rear seat of the truck so the cats could ride in comfort and watch the scenery. We later found one of the cats was crazy about bison. We also had cat beds on the dinette seats in the camper. The cat pan ended up in the wet bath. That was the only major nuisance because we had to move the pan and sweep the floor before taking showers.
Only the first few weeks were tough on the cats. They wanted out and to return to our previous house. One escaped twice. First time she huddled under the camper. Second time she ran out and found 3 feet of snow everywhere. After those incidents and a few weeks of travel they settled down.