Nice. My 65 Newport 4-dr is my current daily driver. You might want to post on forcbodiesonly. They don't get many posts (several codgers hang out there you have to ignore). That is a nice car lift, but I would still be scared to get under there. I jack my cars as high as possible and put a lattice of cut 4x4 posts under the frame rails before I venture underneath. At least you have a lot of room to clean up the rust underneath.
Doors shouldn't be too hard to replace. I replaced 2 so far, buying from Arizona. It looks like you might be able to repair the front door, but hard to tell in photos. I use a Harbor Freight weld-on stud puller (~$100). It works better on the thinner sheet metal of new cars, but did help pull out one Newport door enough that I could do a thin Bondo fix.
Your engine has some emission add-ons mine doesn't have that take up space, but otherwise looks similar. I get 18 mpg hwy with my 383. That is possible with good fuel and ignition controls. The C-bodies aren't as heavy as they look. Mine is ~4000 lb. Much less than a Cadillac.
