IMO the question doesn't make much sense, since it lumps all cab sizes, wheelbase lengths, engine/ drivetrain options and camper sizes/weights together in one question. As long as the rig remains well within the truck's limitations, no modification should be needed. The closer you come to the design limitations, mainly RAWR, the more likely you will feel the need to "do something".
Our truck is bone stock, with the slight exception that the worn original shocks were replaced with Bilsteins. But a Northstar Arrow is a comparatively light camper that handled just fine on our equally stock Chevy 2500 HD that we had before the current F-350 SRW.
