You are possibly the first to own up to doing or planning this on this forum. With all the people who’ve ridden RAGBRAI over all the years it is likely that someone or a few have done this. And have gone unnoticed. My wife and I joke about doing something like this with our two cars all the time and I don’t recall what got us started on that. It is the sort of thing that occurs to people however and that means it is possible that some have done this. One does see a few riders on the route going the wrong way every day. I’ve always thought they just heard about the free beer tent two towns back but who knows what they are up to?
I have a motorhome and a small team of people riding with me so we are going to just share the driving among us. It does leave us each missing out on some of the ride but that is the price we are willing to pay to have the motorhome along. If you can get enough people in your motorhome to make the ratio of riding versus driving work out for you then it is feasible.