You can put all the rear suspension springs and such you want on the rear axle but you still have the COG (Center Of Gravity) way past the center of the rear axle toward the rear I'm sure. This unloads your front axle. It is ok to have a LB truck with a SB camper but you usually don't go the other way.
You state that your truck has an 1800# payload and the trailer (I guess you mean camper) weighs 1690#. That 1800# payload on your truck is without anybody or anything in the truck. I would guess you weigh something. :) This takes away from your payload capacity of the truck. Then the camper weighs 1690# but this is with no options or anything inside the camper. I think you might want to put some water in the fresh water tank and you might want to have some propane on board. Maybe some food to eat and some clothes to wear. This all is added weight on your truck that takes it even more past the dry weight.
It is your call what you do but you are getting some good advice here.
People always come on here that have just bought a camper that overloads their rig and then asks the questions but don't want to hear the answers or they cherry pick the answers that fit what they want to do. You have to make the decision to do what you think is right with all the information that is being posted and be comfortable with your decisions. Also if you get into an accident where something on your truck failed because of being very overweight and without the proper weight balance are you ready to live with the consequences of your actions if somebody is hurt.
