I really loved my Toyo Open Country E rated on my old GMC Sierra 1500. Great, great tires. I added a 700lb leaf spring and Timbrens to that half ton and hauled an 8' Six-Pac camper with it. All in *fully* loaded wet weight about 2,500lbs. Here's the thing though... I never worried about the rear axle/GVWR etc. and the Sierra handled just fine I thought. What did happen after only 1 summer of camping though is all the brakes were completely shot and the rear bearings were also shot etc. So it was all the SUB systems that weren't handling the weight well at all. That costs money I didn't want to spend. Bye bye beloved Sierra.
I now haul the same camper on a Ford F-350 dually one ton (1999, used, cheap, in great shape with the 7.3 so it doesn't have to be expensive & can be very reliable) and can honestly say I sleep much better at night knowing my family is likely much, much safer now. The dually doesn't even feel the 2,500lb camper and the better half is much happier being able to load as much extra stuff as she wants now without me always barking about weight.
.02 Best of luck. Gonna go read about F rate Toyos now and start saving some pennies. :-)