Ok here's more pictures. The first 3 are of the right quarter in addition to the big hole.
The rest of the car isn't nearly as bad as the back right. So i'm thinking i should just replace that one panel and patch the rest.
Here's what i'm worried about on the left side:

Didn't sand much but there's actually metal here so it's worth saving:

And also under the rear glass inside the car is all rusted. Forgot to take pictures of that

And here's just a picture of the car. Need to get all that paint off...