I have two cats who are not fond of each other and one loves to go out.
Here's how I travel with them: Make sure your RV is large enough so they can get away from each other. With that said, they just completed a 10,000 + mile trip in a 24' class C and did just fine. I have a large litter box that stays in the shower pan except when we're showering. ;)
For outside, I put the wandering girl in a harness attached to a gallon jug filled with sand. It's heavy enough so she doesn't care to drag it but can if she really wants to see something. Of course, this is only while we're sitting outside.
I find it much easier to travel with cats than dogs. My cats never have to go outside when it's cold or rainy, we all stay in the cozy coach and watch a movie. ;)