You don't necessarily need any hitch extension. I towed lots of different boats behind several different truck/camper combos (all campers longer than the truck bed) without extensions.
Boat trailers tend to have a generous tongue length already, and the pointy bow doesn't cause clearance issues as much as a square box trailer.
The listed dry wight is fantasy-land, in the real world campers always weigh more.
Your truck can handle this easily, regardless of what the stupid rating sticker says, but you may want to get some overloads of your choice.
I like airbags because of the infinite adjustability.
Many here like the blocks that make your factory overload springs contact sooner. Those are inexpensive and work well too.