TurnipMods

As long as it's not hardcore porn mods or copyright issues, you pretty much can do what you want.

If you really want to edit the main menu file it's pretty simple. The packed ba2 archive runs at start up then loads all your extra mods so obviously you gotta have your menu mod at startup. Skyrim's creation kit archive.exe works well enough so just pack it to a lovely .bsa file and gg your done. edit fallout4.ini line: sResourceStartUpArchiveList=Fallout4 - Startup.ba2, Fallout4 - Shaders.ba2, Fallout4 - Interface.ba2, YOURFILE.bsa, <- add that Boom! Your menu edit works. Time to get menu modding again Mofakin!