Thought I'd bump the thread with some progress pics. This is not going to be a cosmetic restoration--that is going to be way too time consuming given how filthy this machine is. For now, it's a teardown, thorough internal cleaning, brand new wiring, and put back into use.
The old grease in this machine had long since separated out, with all the oil being long gone and the thickeners/additives being left stuck inside of the machine. It was a thick, tacky waxlike coating over every single moving part. The whole inner workings were completely gummed up. I had to really pull hard on the quill just to get it out after removing the raise/lower gear. It was essentially glued in place.
Weirdly enough, the original 37 inch belt size doesn't want to fit on here. I had to get a 40 inch belt. I liked the look of this green Gates automotive belt, so I paid a couple bucks more for it instead of the standard black.
I found a couple of ancient mud dauber nests inside here that the Shop Vac sucked out. It tells me that despite there being no rust or water damage, this machine must've sat outside for a long time. Ironically, I think the original grease/lack of cleaning saved this machine from the elements. You'd never know it was sitting out by looking at it, there's no rust anywhere and all the friction surfaces are in great condition.
The front pulley for the quill was completely seized up inside the drill press from all the old grease wax. I had no choice but to hammer it out with a dead blow. It took a few whacks, but it came out. The original bearing is in perfect condition and feels great, so I removed it and sent the other parts through the ultrasonic cleaner. I don't have after pictures yet, but here's what it looked like in situ.
All the grease caked up inside the spring cutout was Brakleened out after this pic was taken.
After getting everything stripped out of the machine, I let it all soak in Simple Green for a few days before running it through the ultrasonic cleaner. It all came out really nice. I had to remove the tension spring from the housing--it was so gummed up between the layers of the wound spring that it would've never been able to get properly cleaned. It was a bit of a chore getting it wound back into the housing, but if you just put the outer hook into the little cutout in the housing and keep tension on the spring as you go around the rim of the housing slipping the spring in, it'll go in fine. Wear eye protection, a face shield, and heavy clothing for this job. You can easily lose an eye or get a nasty laceration if you lose the spring and it busts out on you.
I opted to leave all the original bearings in. The quill bearings I actually tried to get out, but all I was doing was chewing up the retention hardware and decided to quit before I went too far and messed them up. This meant that the quill couldn't be soaked and had to be cleaned by hand. It was absolutely caked in grease wax. It took half a can of Brakleen, a heavy bristle brush, and a pick to scrape everything out of all the grooves and get the surface cleaned up. No wonder it was completely seized up.
Perhaps the crown jewel is this beautiful old GE motor I grabbed at an estate sale this past weekend for $13. It runs buttery smooth and dead quiet, and the centrifugal switches are nice and snappy inside. It weighs about as much as Honda Civic and probably has enough mass to have its own gravitational orbit. I see no reason to tear it down or do anything to it other than clean up the contact surfaces for the wiring and maybe give it a quick wipe down. I did flip open each of the oil ports and add a nice helping of fresh 3-in-1 (the 20 weight stuff made for electric motors that comes in the blue label bottle).

The only issue is that the new motor has a 5/8" arbor, whereas the motor it came with has a 1/2" arbor, so the original Delta pulley I bought for the other motor no longer fits. I'll hold onto it in case I came across a speed reduction mechanism that can use it, or I might just sell it to recoup some costs. For now, a new 5/8" 4-step pulley is on order.
I'll update this thread with more pictures once I get everything back together.