Good points, Synap. I recall a guy who put burlap bags over the tires of a parked rig, so the sun wouldn't get to them. And I believe owners of the big "serious" RV's sometimes use tire covers when they set up in one place for a while.
If storing a rig for some time, you could block axles -- or outboard suspension points, if it doesn't have solid axles -- up just so the tires were a fraction of an inch off the ground, then cover the tires. Even opaque plastic bags would do it.
Anjou, go ahead and drive that rig that's been sitting for a years. Let us know how it goes.