This gets discussed ad nauseum on here and opinions vary as widely as they possibly could. Some responses are downright comical, like "where you're picking the camper up from" may determine the suitability of the truck. (Assuming you're not hauling it from the neighbor's driveway to yours!)
In short, 4500lbs is a walk in the park for your truck. With OE springs only, it may sag a bunch, but I doubt seriously if it will bottom it out.
After seeing what you want/need to add to the suspension, you shouldn't have any qualms with hauling that camper anywhere, or towing with it, with the proper hitch setup.
Heres where the weight cops will go nuts, but I've hauled my 4500lb camper on my short bed 2500 srw truck with as heavy or heavier trailers than you're proposing for thousands of miles, including the Alcan, which is rougher on the truck chassis then probably any long stretch of road in the L48.
Btw, my truck and yours, have the same frame, brakes and axles from 2500 thru 3500drw.
To make you feel better, go look up the payload cap for the same truck as yours but in a 2wd single cab gasser. Add another 500lbs onto your empty rear axle weight for your crew cab and you'll see that it's rated well over 2 tons.
That will tell you the chassis is rated for it. Additionally your rear axle is good for 10k and so are your rear tires. You'll be around 8-8.5klbs actual load.
Let rip.
