I'm not sure if it would work, but:
OnMiniGameLeave - self - savevariable - client [blah]
OnMiniGameJoin - self - loadvariable - client [blah]
It might register the save variable, AFTER the player leaves, so it wouldn't save anything, because there is no client / player to save from. If that is so, I would suggest save / load points around the map or whatever.