Rusted out support

[Xltsportfun]

I wanted to ask what other people have done to replace the inner rear support (from the cab support bushing to the rear lower corner of the 1/4 panel) my 1/4 panel has rusted off of it and theres a hole clear through the support itself and when its not covered in mud its rusting up a ways, im also going to have to see how bad it is around the tailgate (where the carpet gets screwed down to the floor, not the tailgate itself)

 

[Xltsportfun]

Took out the tail light to get a better view of the piece im trying to figure out how to replace, top left, all the way down to the bottom of the 1/4 panel