Ya, no inherent issues slicing and dicing a flatbed for your needs.
Also not a huge deal to have a cog a little aft of the rear axle on such a big truck….except they already ride horribly and adding weight to the FA helps that.
A 4500-5500 never rides good unless there’s a snowplow hanging off the front!
I thought you already had the truck. I’d think it much easier and more advantages than drawbacks to having a folding “deck” on the back of the flatbed.
You’d still have to get a camper all the way onto the bed. Or at least no vertical overhang in the rear. But a folding deck has some advantages. Can build it relatively lightweight. Can remove it easily for other truck duties. It’s up and out of the way while traveling and most importantly not getting covered with mud driving around the great state of AK. Also you could build it fairly long for a huge deck if you wanted. Although length = weight.
Downside is having to drop it down to access the camper every time unless you can get maybe 2’ of flatbed overhang past the camper.