As you said in the other thread, the .csg files in your players folder should save your campaign progress, including medals and kill lists. (The wiki says these files have been deprecated and replaced with .cs2, but I'm not sure how new of an FSO version does that; whatever version I have installed still makes .csg files for a new pilot.) You'll also want to back up your main pilot file with the extension .json. If you've changed any control presets, I think those may live in the presets subfolder, so probably best to back that up too. (I don't know if those are a duplicate of what's in your pilot file or their own thing entirely.)