There are three unavoidable truths in life, death, taxes, and it weighs more than you think it does.
Your truck weighs more than you think it does so it has less payload capacity than you think it does.
The camper weighs more than you think it does, so you will be closer to the payload capacity than you think you will be with the empty camper.
Your stuff weighs more than you think it does, so you will be farther over the payload capacity than you think you will be loaded and ready to camp.
That said, lots of people have plopped 2000-2500lbs in the back of a 1500-class pickup truck and blissfully travel from point A to point B without a care in the world. There is no law saying you can't.
The "safety card" is way overplayed in these situations. You will feel unsafe and uncomfortable with the truck/camper combination *LONG* before you are actually a hazard on the road, if you are an average, reasonable human being.
There are people that can drive a vehicle with two severely soft tires, muffler dragging, shaking violently, mushy brake pedal, half a turn of slop in the steering wheel, and not notice a problem, but most people would quickly realize that the vehicle was unsafe to drive. As long as you're not someone like that you will be fine.
