Thanks to all for the comments.
I called Hankook before installation to confirm what you have posted for weight recommendations and I agree that the tires are marginal.
But I reasoned this way.
My top speed is 65 mph on a crowded Interstate, 60 mph when traffic is limited. 55 mph on the two lanes.
When I checked the tires for heat buildup it was not present using the palm of my hand for temperature testing.
My total camper build out is well under 1000 lbs, probably more like 400-600 lbs. road ready. i carry 40 lbs. of water, two trolling motor batteries and a 20 lb. propane tank(And a bed, tools, spares, stove, frig, pots, pans, clothes and electronics.) (No co-pilot!).
Running the tires at 42 psi is well within the suggested comfort pressure spec'd by MB and Hankook although Hankook would rather see 50 psi if higher speeds or ambient temps are to be sustained.
My total weight does not exceed 8720 lbs.(Probably more like 7000 lbs.)
I am light in the back but the rig feels balanced underway, in fact solid without harshness and quiet.
I am more concerned about the front tires.
What am I missing?
bill