I know it's not something you would agree with, but as a lifetime PA. resident, with a whole lot of experience in the construction industry (dealing with moving heavy equipment, driving class 6 trucks, etc..) I really think you are addressing an issue that only exists in your mind. Based on experience and discussions with law enforcement, you have a better chance of being struck by a meteorite than being stopped by a "creeper cop" from PSP motor carrier enforcement, and directed to a scale, while pulling your fifth wheel, or being asked for you CDL by ANYBODY in uniform in this state, while pulling a fifth. They can literally pull a dump trailer garbage hauler off of any even numbered interstate, and write a page of violations, in half an hour of inspecting. They aren't going to waste time screwing with a squeaky clean recreational hauler. They simply couldn't care about you and your fifth wheel. It's no different than getting a state inspection sticker on a trailer. I spent decades pulling well maintained, perfectly safe, recreation trailers that never got an annual PA. inspection. The reason? It wastes half a day of my time, and cost $75+for somebody to pull a wheel to tell me that my brakes are good, the breakaway functions, and the tail lights work. All information I already knew, and don't need to waste my time and money on, to satisfy the government. If you ask a typical PA.LEO where the inspection sticker is on a trailer, they haven't got a clue, and 99.9% of them could care less. All of PA. law enforcement has far more serious things to concern themselves with.
I strongly disagree with your claim regarding the "way it works when you are pulled over in PA." In fact, I would argue that that pretty much the opposite of the way it works, since most LEOs don't know how to determine, or give a rat's butt hair about, what your Fifth weighs, and if your pickup is rated appropriately. As for your concerns about being "impounded" Seriously......... this is a rural state with a limited police coverage. You can't be serious?
Not mean to be offensive in the least, just the facts.