Wow - That's quite a mess. But cleaned up great on outside. Being in the middle of rust work on my car (interior also out), I suggest you have a look at the hood hinge pockets. On my car, the seams at bottom of pockets had rusted through and were letting water into car causing rust in various places.

Good Luck with it!

__________________
Graham
85 300D,72 350SL, 98 E320, Outback 2.5