['76 Big Block]

Help!
I've finally started getting around to repairing/replacing rotted areas of the cab on my '76 step side.
The driver's side wasn't too bad, but the passenger side was a real mess.
By the time I knocked off filler, cut out rust, etc. there's hardly anything left in the space between outer rocker and floor.
I think I could make the piece(s) needed for the transition, if I had a photo to go by.
This truck will be a daily driver, so I'm interested in getting close (door fits, cab seals okay, etc.), not looking for a new cab (which is what I'd be doing if I were going for show instead of function).
Thanks for any help!