I take both my cats camping. Not this past year, but we will be doing more in the near future.
When in the car or motorhome or trailer, the cats ALWAYS have their harnesses on. The harness has an ID tag with their name, my cell number, and the license plate numbers of my car and trailer (have a different tag when camping in the motorhome with its license plate number).
Cats sleep about 20 hours a day. As long as they have a quiet comfortable and safe spot in the camper where they can relax, they should adjust to spending their days there.
Travelling is a bit different. Some cats don't do well with the movement of the vehicle. How does yiur cat handle car rides? That will be a key.
Remember some cats do better being able to see the world as they ride, others need to feel safe in a dark spot where they can't see out. You need to account for these differences.
With a short ride, the cat never gets accustomed to the motion. So try taking the cat out for a long 1-2 hour drive and see if she settles.
Both my cats prefer to see out and hate to be confined in their carriers. In the past, I let them loose in the car and after 30 minutes or so, they would find spots to curl up and sleep. Now I have a rambunctous puppy, so in the car I will try their crate (I carry it on all trips for emergencies). In the motorhome they can go up on the caboverbed to get away from Tornado-Dog, so they can remain loose.
The big concern is opening doors. I never open a car or camper door unless the cats are leashed. I also use a 15ft nylon tether for them. I attach one end inside the camper and the other end to the harness. This way they can come out and explore outside safely. 15ft is the longest I use so they can't get into trouble.
The best thing you can do is to practice each portion separately. Take the cat for a few longer rides. Let the cat go in and sleep in the camper - feed her while she's in there. Do more interactive play with her using toys to make up for the lack of space.
Take her out on walks using a harness and leash. Make sure the harness is secure. Remember a cat is very flexible - never pull on the leash and harness when the cat is facing you, she will slip right out of it no matter. Always keep behind her. If she gets scared and turns to you and hunches, stop, get down on her level and coax her to you.
1975 American Clipper RV with Dodge 360 (photo in profile)
1998 American Clipper Fold n Roll Folding Trailer
Both born in Morgan Hill, CA to Irv Perch (Daddy of the Aristocrat trailers)