I'm thinking of doing a clean reinstall of my Win10 OS due to continuing errors I get, but would naturally not have to restart playing. So far I have not been able to easily find locations where I could save (and later copy back in) my game location for the Dreamfall Chapters SE, The Witness & Firewatch. Can anyone possibly help me locate the appropriate file(s) to save? Thanks!

I don't have any of those games installed, but check what is said in these threads

http://redthreadgames.com/forum/topic/757-save-game-locations/

https://www.reddit.com/r/TheWitness/comments/439qno/where_are_the_save_files/

http://steamcommunity.com/app/383870/discussions/1/412446292777219097/#c412446292777246339

Save game locations may vary depending on where you bought the game. For example, Steam may put them in a different place from where GOG puts them.

In some cases, different parts of the save are in two different locations.

Thank you for your help, Jenny.

I don't have Firewatch, but Dreamfall Chapters used to stay for me at C:\Users\*Yourname*\AppData\Roaming\RedThreadGames\DreamfallChapters.
And The Witness - C:\Users\*Yourname*\AppData\Roaming\The Witness.

Thanks Iurii.

A belated big thanks to Jenny100 & Iurii!!