Congratulations and Welcome.
is one of the easier years to rebuild. Save everything you remove, If you don't want it, someone desperately needs it.
Many horror stories about the windows, but they are not complicated to overhaul, and nearly every part is available. They're a tad delicate, but beautifully styled to the exterior form.
As you already know, early issues to address are axles, tires, brake systems, boiling battery, seal shell. sag, separation... an unending list.
I moved the battery off the tail and ahead of the wheels.
I tossed(recycled) the univolt, Breaker box, fuse panel, and "central control" for a Wifco converter. If your tank monitors are accurate, call the Pope, it qualifies as an Airstream Miracle. If you need to know the level of black tank, look in the toilet. If needed, I use a gauged stick to read level of freshwater through fill port. The "central control" analog volt and amp gauges don't read with the precision that battery management requires.
I have three years into my restoration and am very pleased. I have a lot of fun with it on and off the road. I know that it will never be "finished" so I enjoy the restoration journey.
The Airforum google search will answer every question.
'68s RULE! Lightweight, Narrow, Last year of the twinkie tail, with plenty of real wood interior.