You might wish to consider whether it's advisable to utilize jacks for levelling an Airstream. The frames of some AS are not capable of being used to support much, as indicated by the rear-frame injury some suffer from bottoming out and the advice to avoid rollers, etc..
If the frame is supported other than at the axles and tongue it may be possible to seriously hurt your trailer. (I'm not talking about multiple-supports, such as should be used when the axles are changed-out. I mean such as at the corners where stab jacks are used. Those on the rear might be harmful if too much weight is lifted.)
Eric, it looks like you've already made good progress and the next suggestion might be too late for your interest...but, ...
Another method to deal with rust may be to use Ospho or phosphoric-acid rust treatment. This will convert the rust (iron-oxide) to a hard, protective surface treatment that can be painted directly over the treatment after it dries. I've done this on other steel structures and utility trailer frames and it's been very satisfactory. (When I win the lottery I'll buy Thor and we'll start galvanizing them like salt-water boat trailers.)
Joking-aside... I can't see why a shell-off restoration wouldn't make use of cold-galvanize paint. It's been 20 years and two hurricanes since I used that stuff on bare 4" angle-iron at the Gulf-coast beach house and there's virtually no rust and the grey galv.-paint is still doing fine. It's not a glossy-look, but it's durable, and except for the A-frame/tongue, not particularly visible on an AS.)