Like others have said, think about the kind of traveling you will be doing. I don't think I would ever full time so I don't want to be hauling a big 5th wheel around. I have a friend that has one and it is really nice to have the room when you stop. I drive a 23' motorhome and I can stop just about anywhere I want. My previous motorhome was 27' and there were places I wouldn't stop because of the extra 4'. I really miss the room I had, especially when I travel with anyone else. I feel like Beth about the Class A's. I am use to driving trucks so a Class C feels like just another truck. All that glass would take some getting use to and I would be worried about where I could stop.
Try some trips with what you have and see what you like and don't like about it. Cats don't take up much room except when they get on a tear and that only lasts 5 minutes. Mine spend most of a day sleeping or looking out the window. Or sleeping in the window.
Martha