Hi, although I have the Rancho RS9000 shocks also. I don't think you'll be able to use them to 'relevel' your truck with a 3000+ pound camper (I have the Lance ll30 and loaded it weighs in at just a little over 3400 pounds).
I have Air-Lift air bags with inside controls and onboard compressor and find that it takes 70 pounds of pressure to 'relevel' the truck. These bags are rated at 5000 pounds, I haven't seen any reference to ratings on air-pressure on the Rancho shocks but doubt you'll be able to relevel your truck with them.
On a side note... If you have the camper package with sway bar, the drivers side lower shock bolt can't be removed without lowering the sway bar (four bolt mounting on the underside of the axle, there is very little pressure on this so you can do it without a jack). When you reinstall the shock bolt simply put the nut on the side with the sway bar side.
The front shock are mounted to the top of the axles on the 4X4 so, you'll have to remove the shock tower bracket on the top to remove the shocks... not a problem, nothing to be scared of... note: the front shocks are gas filled whereas the rear shocks are not?
I have the Rancho's set at the #4 position and the ride unloaded is softer than stock. Haven't tried it with the camper yet but suspect I won't have to change the setting.
When mounting the Ranchos, the drivers side rear has to have the dial facing toward the back of the truck, the passenger side rear toward the front of the truck, the front shocks should have both dials facing toward the back of the truck to shield them from "road junk".
I dunno, just my experience.
Charlie
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Y2K 3500, 4WD, Auto, 3. 54, Custom Brush Guard, Mopar nerf bars & rock guard, Camper package, Towing package, all options except leather, Lance 1130 Camper