Cats first training in a car for a month wherever we went. No cage had to be careful about getting on/under driver but they learn. After that MH travel no problem. Always had a collar and then harness full time. 6' red leash while driving so we know where they are. Water and food in the front area, litter box in the closet with door propped open, shower an option.
We're careful about them getting out of the MH. It happens and we have the option to leave the red leash on. Use a rope sometimes and they always wrap around something.