Bigger job than I thought, should have got a transmission jack. That thing is HEAVY. I managed to guide it down with my jack, putting brake discs upon towels, and slid it out along concrete floor. Will definitely need a good jack to get it back in, and probably a helper.
Now its PB blaster and disassembly. I’m a little concerned, around right engine mount there could be more than just surface rust. Doesn’t ‘sound’ as good as rest of subframe. I will find out soon enough.