The only working way is the way I am going to tell you. Mine was not in any "Social Club" location. I found it this way:
Download "Quick Search" by Glarysoft.
Use the program to search for "SGTA".
You should see the path for your saved game.
Mine was at this path:
C:\Users\Mistake\AppData\Roaming\Goldberg SocialClub Emu ...