Actually replacing the axles is pretty simple. The problems are 1.) finding a trailer service that will jack up your Airstream properly and 2.) Getting replacement axles that are exact fit with the correct capacity.
#2 can be solved by sourcing your replacement axles from Colin Hyde in NY. He is the reigning guru of all things axle. He will drop ship you what you need.
#1 is problematic — the way an Airstream is built, as a semi-monocoque structure, ensures that bad things happen if they are improperly raised.
How far are you from Jackson Center?
Sorta new (usually dirty) Nissan Titan XD (hardly paid for)
Middle-aged Safari SE
Young, lovely bride