OK, my opinion on why moving up from C to E is a bad idea; but C to D is a better option.
At the risk of starting another "flat tire" thread;
I will throw this out. When I had my Carlisle blowout, I researched this issue ad nausea (as readers of the flat tire thread can attest) and reached the following conclusions.
Tire wear patterns will be a direct result of over or under inflation for the load placed on them. Any tire site will confirm this.
A C tire rated for 2150 pounds (plys and stiffness) with a 2000 pound load at the correct inflation pressure for 2000 pounds will have its entire tread "face" in contact with the road with even pressure across the face. It will spread out (squish) to its optimum width for load bearing at that PSI. That "footprint" will depend on tire construction (plys and sidewall stiffness), internal pressure, and load.
Over-inflation FOR THE LOAD (ie running the E rated tire at 80 PSI) will cause a balloon like tread with only a small part of the center of the tread in contact with the road. This will cause the center of the tread to wear much more than the edges. Since it will have less than optimum tread in contact with the road for stability and control, over inflated tires will be less efficient during braking; the hard tires will bounce more causing more stress on the camper and its contents; and will be more likely to break loose during a panic stop.
Underinflation for the load comes with its own problems. Under Inflating a 80 PSI tire by 35% (50PSI), to conform to the load requirement to have the proper amount of tread in contact with the road, will cause heat buildup in the side walls and early failure.
IMO the advantage of going up two load ranges (increased ply and therefore increased road hazard protection) is outweighed by the disadvantages.
Having said that going to a D range tire (2540 pounds at 65 PSI), will give you extra plys for strength and road hazard protection, yet correct inflation for the load (even a few extra pounds for safety - like running 55-60 PSI instead of 50 - provided your rims can handle it) will still give you plenty of rubber in contact with the road; less bounce; and the ability to go 70 MPH with ST tires safely (according to Goodyear and Maxxis) due to the extra pressure. This is only a 10-15% under max inflation and should not increase side wall temps significantly.
For these reasons I have Goodyear Marathon D rated tires on my camper.