FWIW, I had a different experience when I changed tires on my last camper. When I went to my Maxxis dealer to look at the M8008 ST, they were very familiar with the ST v LT debate and they preferred the LT for my setup.
They steered me to the Maxxis Bravo commercial series tire. They told me they sell a lot of the Bravos for campers. Low rolling resistance and an E sidewall rating and a 3-ply sidewall in some sizes. They were very similar in cost, actually a little less I think. I had them for 2-3 years before I sold it and was very happy with them.