I'm in the middle of the same thing, as I just bought my first Class A gasser a few weeks back. Correct tire pressure and air bag pressure helped. It had been pulling to the right and the shop found the steering stabilizer was binding. They removed that (it was aftermarket) and it now tracks straight. So I'm ordering a new stabilizer this week to tighten up the steering. Next will be a Helwig rear sway bar. My shocks are new Bilsteins, so I'm good there.
Just a comment - I'm coming to the conclusion based on info from this website, my shop, and the mechanical engineer that works for me (he does accident reconstruction and truck files) that most gas class A's have a high center of gravity and a long overhang after the rear axle, and as such will never handle like a diesel pusher or even a box truck. We can only minimize it and make it livable. I have noticed that on the highway the closer in speed I'm going to the trucks, the less "push" I get from them.
Al