Forget the 4x4 part....
There are TWO basic concerns at play here.
1) GVWR which means truck, contents, fuel, passengers...the whole enchilada...are you OVER that limit?
2) More to the point here, what is maximum the REAR axle is rated for and when you weighed everything in #1 above and got the GVWR and the front and rear axle weights separately....what was the REAR axle weight?
Now....the $64,000 Question is: Are you running with excess weight on the REAR axle and how much?
If not then everything is cool...if you are, then by how much is the gamble you take in being able to STOP in an emergency and if the truck will survive a fish-tailing experience from a semi-truck going the other way or you blowing a tire on the rear at freeway speed. Beefing up a suspension is a false sense of security in my book...others will defend the practice when simply buying MORE truck ( a 3/4 ton or 1 ton) would take them OUT of the "red zone" and into the green zone unless you are carrying boulders or something in your camper!
Hey, its up to you though to decide if you have "enough truck" for your fully loaded camper/truck no matter what camper or truck combination you want to put together.