I just picked up an 02 D2 and it has a harsh ride I feel every bump - pebble on the road. I also have bad cupping. I had the tires aligned and they were in spec. I also checked play in the wheel and did not see any wiggle side to side or top and bottom. What contributes to the ride harshness and the cupping.
Don

 

Need more information. How many miles on the truck, what brand tires, what air pressure???

 

there are 100k mi and the tires are michlien 4x4 @ 32psi. Shocks and linkage are orginal equip.

 

Rover suspensions are long since gone at your mileage. The fix, new shocks and springs, Old Man Emu, the best choice.
As for the tires, once they have become cupped, there is nothing you can do with them, either wear them out or step up to a new set.
If you want more information, send me a PM and we can talk more specifically.