We have traveled with 3 different cats, 2 at one time in the beginning, now down to 1 younger cat. The other 2 have since passed on.
You won't know exactly how your cat responds to traveling until he's gotten used to it. At 1st he may be quite scared, hide under the couch &/or get sick. Let him find a dark cozy place to hide, we found 2 of the cats spent a lot of time under the main couch, accessed that area by "going down the rabbit hole" an opening between the corner of the couch and the counter top at the wall. If he is very comfortable in a crate that may work best for him too. Or he may find it comforting to ride on the passenger's lap.
Our latest cat hasn't been on the road much but each time she has been scared and ill at ease especially when the engine is running and we are moving. I don't think she will ever get used to traveling as much as the other 2 did.
We've been told by other cat owners the worst issue is the cat getting out the door or window. In a scary situation almost any animal's instinct is to run. It is almost impossible to get them back because they are too scared so just run and keep running and will not come to you even though they may have at home and sadly may be lost forever.
Therefore we devised a system. The whole time we are rolling the cats wear a harness and collar with a leash hooked to the collar then leave 3 -4" length then tie a 1/2 knot in the loop at the top of the harness. We found a small dog harness worked best. A cat can and will get out of a harness in just a few seconds. The collar needs to be a regular collar not a safety release collar sold for cats. Both pieces need to fit well so they won't come off easily. The leash holds it all together and the cats learn to drag the whole deal around. We take the leash off when parked. The leash gives you that last attempt to stop a cat before they get too far. Believe me we've had a few close calls when one of them would try to get out the door at a fuel stop. The leash saved their life! It worked...we traveled for almost 10 years and didn't lose one cat. In fact the younger of the 1st 2 actually would go on walks with us and the dog on her leash as long as there weren't too many other dogs walking around her.
Care has to also be taken when going out for the evening...a sneaky cat will sit at the bottom of the door step and wait for you to open it, again, looking to go out snooping around.
A good second option while you are rolling...keep the cat in a carrier until you are parked.
We put our litter box under the bathroom vanity an kept one door open all the time.
Good luck
2002 Tiffin Phaeton
2005 Malibu Maxx toad