5th wheel. Period. If it were just to have some amenities for the wife and kids on the boondocking trips then any clapped out bumper pull shitbox that doesn't leak would work but if you guys plan to use it for more than that, go 5'er. I'll never have another bumper pull RV. Biggest drawback to having a 5'er is the length and not being able to fit into state/fed campgrounds if that's a thing for you.
As far as reclaiming the bed of your truck, this is what I have
https://pullrite.com/products/superlite - it's the opposite of the Anderson and I have had zero issues. They make them for both the gooseneck or bed rail setup, depending on what your truck has. I can 1-man lift that in and out all day long... biggest drawback is that friends don't have the same setup and I can't snatch their trailers from storage or vise versa... no actual drawback to the hitch itself.