So how lifted is it?
18'' wheels does not effect anything as its the tire size that matters.
My 2011 Dually had a 3'' leveling kit and Supersprings on the rear also brought up the rear. I had no issues with it. Looking at doing the same on my 2016 dually.
I personally wouldn't do much more than a leveling kit if I was hauling a truck camper and or towing a large trailer.
On a SRW with a lighter camper or popup camper I could see doing a 4 to 6 inch lift on it for fitting larger tires for offroading.
So far in life my 2016 is the only truck I have owned that has not ended up being lifted or leveled out :)