I know you don't want to hear this, but that machine is in pretty sad shape. Cleaning it up isn't going to help the ways and lead screws. Just saying thata you'll have a lot of money in that machine before you're making chips.
JR
Not sure what you are basing this statement on. Bridgeports are designed to accept wear, with adjustable gibs, lead screws etc. No way for us to know from here if your machine is badly worn and rusty, or just rusty.
My machine was a little rusty when I got it. Maybe not as bad as yours, but definitely not well oiled. Under the rust were good scraped surfaces.
I cleaned my table with WD-40 and a green scotch brite pad. Came out looking pretty good. I would not recommend electrolysis. Read bradjacobs step pulley thread for his detailed instructions.
Also, I wouldn’t wait for the magic lube to start disassembly. Hose it down with WD40 and get to work.
I found purple power to be a effective cleaner, degreaser, that seemed to remove rust pretty effectively.
Only part of my mill that gave me any trouble was the ram. Daily doses of WD-40 for a few days running, standing it up right on the floor so the oil could run down seemed to help. After a few days, a rap with a dead blow hammer freed it up. Patience helps.
Only way to diagnose your machine is with hard numbers derived from careful inspection. We are super helpful and generally happy to speculate. But we also need to catch ourselves occasionally. We can be more helpful as you provide more data.