I'm the Wiz, and nobody beats me!
Yes, I have gone through those same headaches. I acquired a 63 Schwinn Sierra last winter. It was sitting outside at a farm for at least 20 years, maybe 30, or more. But it had all the original parts (even saddle, which I tried but could not save), so I went all-in on doing a full clean-up. To remove the stem, I used a trick that was discussed out on the forum threads…. Removed the stem bolt, plugged it with a rubber stopper, tipped the bike upside down and filled the head tube with PB Blaster. Waited a month and sure enough, I was able to remove the stem from the fork.
The Sierra also has the 2-prong Atom freewheel on a Normandy hub. As to not destory either, I removed the bearing cover with the pin spanner (after saturating in Blaster). I carefully lifted off the gears, colleted the bearings, and removed the pawls. I then did my best to saturate the freewheel core with Blaster, then wait for it to work itself in. I wrapped the core with a thin rubber cover, put it in a bench vice, then carefully turned the wheel until the core busted free.
Using the #8 easy out is the only way to go IMO. The metal on those freewheels is like a bronze material and it just can't take any force before you peel it right off. And I do mean peel, like a potato skin. Been there. After that I decided to use an easy out, and it wasn't until some years later that I actually saw that method being shown in the Schwinn Repair Manual. When those freewheels have been on a hub for 55-60 years, they want to stay there.