Go back to the drawing board. Your numbers don’t make a lot sense save for the total trailer weight of 3-3.5k.
1. Virtually any TC with a 2klb dry weight likely won’t need a 3’ extension. Not even if your truck is a short bed.
1a. Or your camper is much heavier if it’s a 9’ model on a short bed or a 10-11’ model on a longbed.
2. 600lbs tongue weight is excessive but probably necessary because you’ll have to back the buggy on that little trailer due to being single axle and the weight of dist of a rear engine rig. You have no adjustability in weight placement effectively. So yeah maybe. But I’d figure out how to lighten up the tongue weight a little.
You’ll have no issues with the truck, hitch receiver or a quality basic extension at 24-30” long. I can’t speak for longer with the same or similar tongue weight.
A weight dist hitch in this scenario seems somewhere between heavy, useless or may not work right. But your truck and hitch will handle it so it’s also not necessary with your little trailer. Interested to see it employed successfully if you do it though.
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