I live in the snow belt, we use salt in the winter and it eats away at cars...the Shadow has tons of rust along the lower body, and a rust hole in the driver's side foot well.
First gen Caravans, and to a lesser extent, 2nd gen Caravans are notorious for rusting on teh rear hatch where the lower window seals are...I don't know why. Oddly, our `86 never rusted there. It did however, rust on the sliding door, driver's door, passenger door, and where the rocker panel meets the rear wheel well on the driver's side...currently it's the only rust spot now. Water apparently collects there and doesn't drain out properly...which is why it rusted there.
I notice only small rust spots on the 3rd generations vans for the most part...probably paint imperfections. Most (that haven't been in accidents) hold up pretty well. A friend of our family has an `03...it has rust on it where it was damaged and they never bothered to repair it...not the van's fault. However there is a paint blister on the left corner of the hood...I suspect it will start to rust.
My car has a rust spot in a strange place...on the driver;s door frame at the top (not the roof itself). I plan to fit it this summer...it's only surface rust...I have no idea why it's there of all places, but it'll be fixed before it can spread.
I've seen some badly rusted Chevy Ventures...worse rust than older Caravans..one was white, and had a rust hole bigger than my hand along the lower rocker panel on the driver's side.