Sounds like water mixed with rust/corrosion. Not a good sign for the engine and radiator. Not to be discouraging but so far you've got two very big strikes. 1. Quite a bit of rust in areas that are a pain to fix, and 2. Quite of bit of work to the engine(not that bad because you can get pretty good engines on the board for reasonable prices). I hate window seal rust. I've used some metal based fillers in those areas but personally have never had much luck in getting them perfect enough to seal real well. IF you're up for a very big project though I say go for it, bring her back from near death.