Welcome to the Forums!
Looks like it is a
1960 Tradewind, 24' long.
My guidance regarding renovating a vintage Airstream would be to hope for the best and expect the worst, and plan a shell-off from the beginning.
You can feel your way there by getting out the buyer's inspection checklist, going through everything, making a list of what needs to be repaired, and then tackling it one project at a time, starting at the "deepest" level of disassembly and working your way out. Or you can do the following:
1) Spend up to two years looking for the trailer that is in the best shape, with the best price, with the best floor plan, only to drive too far to look at a trailer, and buy it out of desperation, as you don't want to go home empty handed.
2) Remove the interior including all inside skins and insulation--store it in a temporary shed (that will become permanent).
3) Build a set of gantries--you'll need them.
4) Lift the shell (using the gantries) from the frame and set aside.
5) Use the gantries you built to lift and flip the frame.
6) Remove belly pan, gas lines, etc., and set aside.
7) Perform all repairs on the frame, address rust and paint (again, lifting and flipping in the process).
8) Install new floor on frame.
9) Flip, insulate the underside of the floor, install retro-fitted grey tanks.
10) Install belly pan with frame still upside down.
11) Install new axles (with frame upside down, using the gantries as a crane).
12) Pressure wash the interior of the shell--make every effort to get rid of the mouse piss and old insulation--this is your only chance.
13) Lift the shell, wheel the frame back underneath, and set the shell back in place.
14) Complete reconnection of shell to frame.
15) Replace all door and window seals, plumbing vent seals, perform any shell patches, panel replacements, AC replacement, etc. (use the gantries as scaffolding to access the roof of your trailer).
16) Seal the inside of the shell, every rivet, every seam.
17) Spray primer on the inside of the shell to not only protect from corrosion, but to seal in funk.
18) Write a mysterious message to the next restorer on the inside of your shell.
19) Rennovate/install any awnings and ensure that any new shell penetrations do not leak.
20) Confirm that your shell no longer leaks.
21) Assess wiring in the shell. Rewire if necessary, realizing what a PITA it will be, trying not to nick any wires.
22) Strip the clear coat off your shell if needed.
23) Polish the areas around the trim, emblems, clearance lights before reinstallation.
24) Thoroughly investigate every kind of insulation known to mankind and then install the pink fiberglass stuff anyway.
25) Reinstall interior skins after thoroughly cleaning them--paint the backsides with primer to encapsulate the old stank you can never wash off.
26) Rebuild electrical distribution system (battery, fuse board, etc.).
27) Layout your future cabinetry.
28) Begin to run water lines, realizing some of them will go under/behind furnishings
29) Start from the rear of the trailer and rebuild the interior furnishings, cabinetry.
30) Lay down new flooring.
31) Rerun the gas lines.
32) Finish installing appliances.
33) Do the blinds/drapes/upholstery.
34) Finish whatever polishing you want to do on the exterior
35) Seal every exterior seam
36) Discover new leaks and throw a fit
37) Throw away all the receipts, as it is just too depressing to know how much you just spent.
38) Count the gray hairs/hair loss that has resulted from the years you have spent on the project.
good luck!