Well, we have a long history of traveling with all kinds of pets, including cats. Some cats traveled very well, never a problem. We always have them ride in the cab of the truck and never had a problem. We just have to watch very carefully opening the door getting in and out.
However, all that changed with our current cat. Now, he's not a very good traveler, great camper, but horrible traveler!
He gets car sick. We tried originally putting him in a pet carrier. The cat was so hysterical in the carrier, he cried and cried and cried until he made himself sick, vomit, poo all over the carrier, and himself! What a mess.
We talked to our vet, who gave us tranqualizer pills. Now that didn't work either. I think it made him even more hyper, and them more sick from the pills. What a mess! Constant barfing, pooing, and pee! Smell, awful.
If we let him loose in the truck cab, he'd crawl under the seat and .... yep! vomit, poo, and pee! Talk about horrible experiences!
So we tried letting him run loose in the travel trailer while in transit! BAD, BAD, BAD mistake! He vomited all over the camper, from one end to the other, cat poo everywhere (and I mean the runny stuff), and cat pee, which is VERY VERY hard to eliminate that odor.
Still, we continued.
We even tried putting the cat litter pan inside the truck, but he'd only go in there if we locked him in (it has a cover). I think he felt like he was in a crate that way, and just paniked.
We tried one of those Thunder Jackets! NOT ON THIS CAT! And then we found what worked best was when the passenger simply held the cat in their lap and the cat was covered with a blanket or towel. AH!!! we were on to something!
Until one day, he vomited anyway! But we were finally on to something!
I came up with the idea (eventually) of putting the litter pan in the shower stall in the camper. It has a glass door and can be secured. We also put the cat in the shower stall and hit the road.
Now if the cat vomits, or whatever, he can either jump in the litter pan, or it can be flushed down the shower drain. At least he's not doing it on our bed or the couch!
Well, actually THIS worked! He never vomited or pooed on the floor of the shower, he DID do it in the litter pan! AH.... success!!!
Until.....
The weather outside got too hot and the inside of the camper would heat up too much for any living thing when traveling.
So, we'd leave the cat in the camper, in the shower, and keep a wireless thermometer in the bathroom and the other end in the truck. When the temperature in the bathroom reached about 90 degrees, we stop, take the cat out, and bring him back into the truck. By now he's all vomited out! And sitting on the passenger, covered with a towel or blanket, he did fine!
Now we have a win-win situation! FINALLY.
Our routine now is to put the cat in the shower for the first 20 minutes of wherever we are going. This gives him opportunity to (literally) get everything out of his system, and then bring him into the cab of the truck where he sleeps contently on the passenger lap, under a blanket for hours and hours and hours!
For us, this is the ONLY way to do it with this cat!
Once at the campsite, the cat absolutely loves the trailer. He has absolutely NO desire to go outside!
That's how we do it!