Second hand knowledge.
A co-worker had 35X12.5 XTerrains on his Jeep and loved them. They were quite and got great traction. His jeep was not his daily driver, he only used it for hunting and off roading. He got another job and moved out of the area. We stayed in touch until he eventually got transferred out of the country. He had something like 10k miles and was less impressed because of their short tread life, but still liked the traction.
They are a soft compound and on a truck carrying a camper you would probably go through them pretty quickly. There was a Chevy Avalanche that I used to see regularly which had a set of Xterrains and I could almost see tread wearing on a daily basis.