NEW Dodge 2013 Ram 3500 4x4 -> ride is horrible! What to do?

It would probably be expensive, and you may not want to molest a new truck, but maybe go to a custom shop and have an air ride seat installed.
Most semis have air ride seat, and they also come on farm tractors,should not be hard to either modify your seat or replace it.
A one ton is not a passenger vehicle and should not be expected to behave as one.