[hypoxia]

On my 2020P coach there is a removable panel in the forward cargo bay which allows access to the front ride height valve.  My experience with ride height valves is that they rarely need adjustment and when they do, the valve is probably going bad and needs replaced.  When the valve is adjusting the air bags completely full, the ride is as you described, it's as if there is no suspension.  I've had that experience.

Tom will probably step in to  give the correct advice for your vintage coach.