Just bought a new Winnebago Sightseer 35G and have noticed that when driving, you really feel the bumps and rattles. Now I expect that because it rides high, I would expect some bumps and not a totall...
Have you weighted your axles? Set tire pressure accordingly? If way over or under inflated, it will be squirrelly. As a begin point, how does your tire pressure compare to that on the GVWR sticker (which is based on each axle being loaded to its GAWR)?
Agree on rear track bar and then (i.e. next step) larger sway bars.