On this site, search Cuda frame dimensions. There are a few threads with all that info posted for your convenience. You can also buy a nice large schematic on ebay for $10 or so. I did just to keep it on hand while I worked.
Looking at the photo, aside from the obvious hood and driver fender, I'm guessing you will be replacing the driver frame rail, inner fender panel, shock tower if you can't remove and reuse original, radiator supports. It is very possible that the hood hinges were driven rearward into the upper cowl. It is also very possible the passenger frame rail was moved somewhat since the K frame connects the two. I could see some of that force transferring into the passenger rail. Will definitely want to carefully examine you K frame as well for twisting.
In my opinion, this is a doable home project. I have a thread going now (saving a 4 speed JH car) that shows a lot of pictures of me swapping these items out myself at home using a home made jig. My car had rust issues but metal work is metal work. I recommend you remove the hood and fender, then support the car fully on some type of jig you can then take reasonably accurate measurements from. I used six large jack stands with thick U channel steel front/back and then side to side. I shimmed the rails where they touched jack stands to make everything solid and level.