A couple Saturday morning updates. Radio works which is huge, the amp is about $800 and very venerable to water or anything else, such as heat. Car only came with one key, that's a bummer, likely 400-600 for a second key.
Dash lights up, mileage confirms with all service records. Battery was at 2.2 volts, and when jump pack was getting errors of voltage too low. I think the jump pack was trying to charge the battery.
More signs pointing to leaves got into the engine water drains, and water backed up into the firewall and then into the interior. Based on the rust on the battery tray, this didn't happen overnight, but based on the lack of damage on the interior unibody, the water didn't hit the interior until very recently. That battery tray rust suggests the passenger side drain was slowly backing up, and leaving 24x7 moisture on the battery tray. No rust or corrosion anywhere else on the car....
Had an old battery laying around. Hooked that battery up, she tried to turn over... Was very surprised. Have the battery the car came with hooked up to a charger at the moment. I am suspecting the car may start with a full battery. My spare battery was a dead and originally uncharmable battery I brought back to life. Its great for testing light bulbs... but can't handle any real load.
Interior electric like the seats, windows and so on are not functional. Kind of bad as I need electric controls working at the passenger front seat to get at three bolts to remove the seat to remove the carpet. Hooked the MB computer to the OBD port, can't talk to the front or rear computer. Could be low voltage, or could be corrosion at a connection. We shall see.