You have torsion axles. It may be difficult to engineer/design a set of leaf springs to install on your trailer. (Change in most of life is a struggle)
With that said the torsion axles you have may be welded as early ones were welded instead of bolted. Cutting and welding or bolting a new set isn't for the faint of heart, however you have already removed the coach so you are already knee deep.
The earlier torsion axles were also not as standardized as with axles used after 1969. So careful measuring would be needed along with knowing the expected max load the fully assembled trailer with all possible gear and fluids installed. (And I would add 10% to that possibility)
A 2 inch movement is pretty good for a torsion axle. Many don't move that much. And a torsion axle that is close to drawing social security is highly suspect. (very highly) And now would be a far easier time to install an axle rather than when the registration and insurance says it is time to roll. I really don't care what type of spring a vehicle has (leaf, coil, metal or rubber torsion) all springs have a limited service life. I restore several classic cars, after 30 years those metal springs get replaced.
Your call as to the next step. If it were me and having gotten to the place you are at now, spring replacement (axle in the case of a rubber torsion spring) would be my choice. I also tend to not change the design of a vehicle. Again that is just me.
1966 Mercury Park Lane 4 DR Breezeway 410 4V, C-6, 2.80 - Streamless.
1966 Lincoln 4 door Convertible 462 4V 1971 Ford LTD Convertible 429 4V Phoenix ~ Yeah it's hot however it's a dry heat!