I thought you had a late model E450. Signature doesn't say but reviewing posts suggests:
Late E450
Roadmaster RSSC Stabilizer/Damper
Front Tires around 60-65 PSI for 4400 front axle weight
When a Ford Twin I Beam chassis sways, it Steers! The Rear End is the Heavy End. No wonder the Brits call it "The Big End..." That's why I think you should control sway starting back there.
Also, with the late E450 using an improved Front Sway Bar DESIGN (not size, still too small) you "might" find the end link bushings are soft rubber. You could replace those with hard bushings, polyurethane, and maybe gain a little more control.
Still, I upgraded both, and added a Blue Ox Tiger Trak rear track bar. I'm glad I did all of those, but if I was to do two of the three bars, they'd both be Sway Bars.
You'll also find your coach has a steadier stance on the campsite...
