If you have the hard drive space, be sure to have a vanilla (unmodded, untouched) copy of GTAV and rename this to Vanilla (or something like that).
Then have youre GTAV file you load up for LSPDFR (modded or not) separate and keep this as the default folder name.
And then when you add mods and addons, take your time and add one at a time (remove which ever mod is causing an issue instantly) and keep this file also separate, to be sure you keep a stable working version of the game (copy paste it and rename folder ie. Working, Stable).
This helped me greatly when learning the modding process.
When it all goes tits up and some how corrupts both your LSPDFR files, delete them completely and start from the fresh vanila GTAV file.
Good luck!