Ok this upcoming Saturday I am going to find out the bad news about my recently acquired 300td wagon which was a pig in a poke.
Going to pull the fenders and battery tray and look for all the places rusty badness can accumulate. I am recent purchaser of the car and I am having a sinking suspicion that the car was recently resprayed, maybe over rust.
Casually looking into the bay I see that the driver's side lower hood hinge connection pin and clip is sitting in the middle of a round hole(?) thats not present on the passenger side. Hoods working fine so I dunno. The inner fender well under the Master cylinder has at the least a lot of surface rust, probably caused by an old brake fluid leak?
I am still getting water in the cabin entering over the emergency brake/hood release which is weird because the back of the hood hinge pockets looked ok (with hinges still in place- I am going to remove to check). The windshield gasket was recently replaced with a factory replacement as well.
Definite places to check:

• Inside of fenders
• Under battery tray
• Pull carpet and look at floor pan
• Hood Hinge pockets
• Rain Gutter and base of windshield
• Bottom of doors
• Jack Points
• Spare wheel well
• Inside of doors

What else, guys? I can already tell this is going to break my heart, but I wanna know the prognosis, doc.

*This might be interesting to you guys: I am planning to spray this stuff (Ultra Ever Dry), everywhere that's vulnerable and unrusted. It's translucent white, but my car is light ivory(mb623) and I won't use it on exposed exterior panels. Not affiliated. If it's a bad idea, tell me why. I had been using fluid flow and like the product but the lanolin is kind of slimy and glisteny in appearance (Put it on my new brake caliper outsides.)

So post your worst and I will update this thread with pics.

Edit: delayed one week due to inclement weather.