The overloaded rear tires worry me more than anything else.
Obviously, the rig drives well enough for you to enjoy it.
The weight police will tell you that you are overweight. Which is true. Eventually, only you can decide if you can live with that.
Someone with more knowledge may be able to tell how much the individual components are rated for (rims, rear axle, frame, etc.).
Can you go to 19.5 wheels?
Nothing you do to the truck will make the fact go away that the truck was not sold for that load. It may well be up to the task, I do not know.
Putting the camper on a dually will give you peace of mind.
So would getting a lighter camper.
Decisions, you got to make them for yourself...