Just wanted to say thanks to all who responded to my post. We ended up going wit the Tidy Cats Breeze pellet system litter box for our two cats. Reasons: zero dust, total system weight about 7 pounds, easy cleanup. Odor does not seem to be an issue after talking to people who have used this system for quite some time. Our plan is to place the litter box in front of the passenger seat when stopped and under the dinette when traveling. Cats are having t adjust to the "feel" of the pellets vs clay litter, and I will have to say they are not overjoyed at the difference. But, they are using the boxes now. If they were new cats or kittens, adjustment would be no issue, I think.