Totally do able. I'm guessing the 9.3 is the length in the bed which is pretty long for a short bed camper.
Length of extension for the hitch will be dependent on the tongue length on the trailer and overhang of the camper.
Ideally a super hitch but if you don't have a lot of tongue weight may get by with just a hitch extension.
Plus that's a light camper if it will be at or under 3klbs loaded up.
I've not towed horses but have pulled 5-6klb trailers all over with my 07 short bed with a much heavier camper and just a 12-18" hitch extension, including up the Alcan hwy to AK.
IMO you got the right truck and 19.5s are not really needed at your weights, again provided the camper weight and cg is reasonable. And the new Rams have a beefier hitch than the one I have.
