So I had the same issue. Removed EUP.dll, mods folder (only had EUP in it) and EUP folder in LSPDFR and now rage loads correctly. I believe that EUP causes rage not to load GTAV correctly. You could start GTAV first, then load Rage with plugins disabled, then RestartAllPlugins in game to see if that works. If it does, see if EUP works with F11. Again, if it works then EUP would be causing issues and most likely I would assume its what it changes in the Mods folder.