Sleeping on air mattress equipped sofa bed ??????

Next summer I am planning an eight-week trip to the West Coast with my daughter and her husband; thus, we will be using the sofa as a bed. The sofa is equipped with an air mattress which is very uncomfortable and reacts every time your partner moves. I have looked at getting a mattress-n-the box to place on top of the uninflated air mattress. The problem with this is that each day we will need to move this mattress to the master bedroom for storage while we are driving on the road. In the past I have used a 4- or 6-inch foam topper on the sofa sleeper or on the dinette when we use it as a sleeper for the kids. However, I suspect that the mattress-n-the box is going to be much thicker than 6 inches and thus much heavier and more difficult to move each morning. We have also considered replacing the sofa with one without an air mattress -- we probably would still need a 4-inch foam topper.

Has anyone placed a 6 inch foam topper on an inflated air mattress equipped sofa bed?

Your thoughts and comments are most welcome.