Serious FO4 data location inquiry

[WallyWallWhackr]

I want to do a backup. I had a load fail some months back and then found those files thanks to folks here and was able to get back that game progress. I thought I moved that location to my second physical drive. But now I look and I see files in a few places. My C: Drive has the main body files under Program Files (x86)/Steam/steamapps/Common at 95.5 GB. Under Documents/My Games/Fallout 4/ is another 2.66 GB. Where I THOUGHT I told your game setting to put my files is on my D: Drive and that drive's layout is in SteamLibrary/steamapps/common/Fallout 4 and is another 197 MB. So are all of these critical to have as a backup? I as yet have no mods and only DLC stuff from Bethesda. I am LV 142.