Ok that helps. Nice setup btw.
So presuming you have an 8.5-9.5’ long flatbed.
The pics of the CM RD beds I see have a fabricated hitch receiver and CM rates them at 18,500lbs.
If this is the case for yours (although it seems your hitch is fabricated into the back plate, I can’t imagine a light duty hitch on a flatbed suited for a class 5 truck) and your theoretical boat is not super heavy, (Another important detail) I’d get a heavy wall tubing extension built and plug it in and go.
You could fab lateral stabilizers from the extension back to the flatbed (like super hitch extension) but imo the bigger concern would be tongue weight. Lateral loads are pretty small unless heavy trailer, no trailer brakes and panic stop in a tight turn.
Small boat, sub 5klbs including trailer and not a lot of tongue weight I’d make an extension.
Big load say 8k and up, I’d be thinking more research needed and calculations of bending moment on extended tongue.
I’d also find the hitch rating from CM if it’s not what they show on their website.
Nice part is you have enough truck to haul that camper and about anything g you’d want to tow, easily. Beyond that you may need a fab shops advice if you’re not comfortable deciding what to build.
BTW , what part of the beautiful state of MT do you hail from?
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold