As I said earlier I ordered my F250 with overload springs which you may not have but shortly after I got it I loaded it with gravel until the springs looked loaded but still had some room between the bumpers and the axle. I went to the scales to see how much I had put on and was shocked to see that it was 6,000lbs. I never loaded it that heavy again but I did often haul 4,000lbs. That is about what my camper weighed loaded for a trip. With 3,400lb tires on it that had them near capacity and the last spring was just touching. The only mod other than bigger rear tires that I made was putting Ranch 9000 shocks on it so that I could adjust damping for the load that I had. I should have done it much sooner. The ride both unloaded and loaded was much improved.
My father set up a very similar rig with a 1995 F250 but on my advice skipped the factory steel overloads and added airbags. In my opinion he had a smoother ride plus had more options for leveling the rig at the campsite.
Neither one of us liked to get over 65mph, mostly because of the noise and fuel burn of the 460 engine. Your truck will probably ride better than ours did plus be more stable with the heavier frame and Powerstroke holding it down. It was amazing how much frame flex we had. Your truck will be much more rigid.