Is it a Leaf spring or a Torsen arm suspension?
It could be done and maintain a relativly stock ride hight for traveling.
Our 59 is leaf spring and it would be VERY easy to do what you ask with it. The frame, Like Andy pointed out , is the issue. It will have to be reinforced to handle a new mounting configuration.
If it were mine I would go to a 3 link control arm configuration. You would have two main links that locate for and aft and a pan hard bar to locate side to side. Use a drop axle so that the tires will already be offset 3 inches off the centerling of the axle.
If you made the main links about 20 inches long and located a set of 2800lb air bags mid way down that lenght to create a cantelever design you should be able to vary the ride hight by about 10 inches with the amount of air pressure you use.
The trick is going to be build a subframe or reinforcing the existing frame to hold the new suspension and not stress the existing frame. One the frame is beefed up the rest would actually be easy.
Ohhh here is nearly exactly what I am talking about.
That is a 4 link. THe top two links work together to control the side to side axle placement. It's a better design but more involved and for a camper were your not worried about pinion angles it's not needed. That truck factory used a single Panhard/track bar.
The thing I want to to look at is how the air bags are mounted mid way down the lower control arms. This allows for a lot of trave at the axle with minimal travel at the bag. That style bag with 50 psi would have no trouble handling the weight or your 63 and maintaining a stock ride hight. at zero PSI it would let you lower at least 5 inches.
Here is a drop axle.
Ran across this looking for a piture of a drop axle.
Not enough travel for what your doing put intersting set up.
Put the bag on the other side of the axle and double your travel.