Short answer on the rust: your a bad influence and I'm just that lucky.
Long answer: I jumped on a car (like a fat kid on a newly found chocolate bar) after missing several others. Even after picking out bubbles under the paint, the floors looked good from underneath. Heck the rust under the heater core is just deep surface. It even survived the "screwdriver test". Driver's side, well not so much (it now has screwdriver size "cooling holes"). Oh, and your a bad influence.
I've actually wanted one since around the time you had the red car. Just want a bit of a sleeper, so this one is not going to see any of the exterior treatment your working toward.
I know the feeling. The red car started out as the worst example of a trashed 4 cylinder notch that existed at the time. I wanted one so badly I paid huge money (2k) for a car that literally needed every piece of weather stripping replaced because it was dry rotted to the point of disintegration, had a really bad paint job, the interior looked like a pack of dogs had a sex party inside,and was sporting a salvage title on top of that.
But what can I say, you want something badly enough you become blind to the "little things".