So I decided to be lame and stay in tonight. Figured I'd work on this sick puppy.
I removed the board. It's corroded beyond belief. Thankfully, everything else appears salvageable with the possible exception of the IIe card. I was able to recover the RAM and I'm hoping the PSU works.
I have another board to fit in here. I'm not sure how good it is, as I haven't booted it since 2002. At least it isn't a rustbuçket.
I cleaned the case up a bit too. The corrosion was from a black battery from what I can tell.
Here's hoping this works. I'm also working on four other Macs tonight (all SEs) so I may be up forever...