I have F4 installed on one drive, and Fallout London installed on a different drive, both purchased from GOG.
Both games will start, the FALON install shows London Mod splash pages. However, I notice if I choose "load" I can choose F4 saves. I believe this is because they both use the same Save folder.

If you played both could you keep both game's saves in the same folder, or should I backup my F4 Saves and set them aside until when I get done playing FALON?

Now Vortex, it does not recognize the FALON install. In that game folder there is a F4.exe, and a FALON.exe. I could swear there was a time when Vortex had a button to add a game to it manually, but I no longer see that. I'm wondering if I changed the name of the Fallout London Folder to Fallout 4, would Vortex now recognize it as a F4 install to allow me to manage and install mods into it. Anyone know?
Thanks!