Double check your weight load range for your truck,
then add the weight of the truck, camper, horses and gear, and start from there.
Some campers are MUCH heavier than others. Dry weight is without all your
"stuff" in it, and without water in tanks. I'd say in general, you should have
no problem with a 9 1/2 foot camper. That is what we have, with a 4 horse Circle
J, 1 ton diesel. I'd get a hitch that is rated for "more" than you need.
Ours is a solid bar, not tubular, and is 2.5", not 2". We also have load
levelers. Photos are here of our hitch, and camper tie downs.