I just retired as of Dec. My Dart has been sitting in its dedicated "shed" for 5 years. I have collected parts till the actual garage is a nightmare. So far got the springs moved and rear installed. Other small jobs too.
To address your situation, first i would get a cork board and a box of push pins(like the detectives on tv do to piece together evidence and suspects). Use your library, notes, etc. to get an idea of where you are and where you want to end up. I had a white board but the cork board would be easier to revise and update. Got to get myself one. (trying to help you is giving me fresh ideas for my Dart) If I remember right you already have the engine out. Start by taking everything out to assess the rust issues. Put Craigslist/ebays part note on the board to look for repair parts/another body. Look around every few days online. Seeing "just ended" on an item that went for cheap always kicks my butt. Then, back away from the sheet metal. Then start with components starting at the rear. Clean, rebuild, replace and paint as needed. Keep moving forward. Sometime around engine build time go back to the body. By now the body issues should be chronicled, parts in hand and ready for completion.
Good luck on the Charger. As a group we can probably help locate parts and pieces as needed. I for one will try to keep in mind where I see potential donors.