Locations to watch for rust

[beljum]

Any of you fellow rust-belt rats have updates on rot locations to watch out for? I'd like to give those areas some attention on my new 2016 before the snow flies.

 

[Piotr01234]

Hopefully I am the only one that this has happened to, but another location is inside the rear doors. Halfway between the passenger side rear door handle and the rear wheel, rust formed under a metal plate that is welded to the door. Rust formed inside and eventually bubbles were seen from the outside. It was covered by the rust through warranty.
Vehicle: 2013 Chev Sonic LT ≈57k miles as of Dec 2017

Below is a link to a google drive folder that has some pictures of it.
Google Drive - Sonic Rust
852, 1384, 1385, 1386, 1388, are pictures of the bubbles
1390, 1398, 1399 are pictures of the inside
1393 is a picture I took with a mirror to see the rust forming in between the metal plate and the door

 

[Chuck Schick]

Thanks for the pictures...