I use ESPN to run my league, and we essentially have a standard scoring league (minus D/ST yards allowed). Anyway, in that scoring format, Gore got credit for the TD, but not the fumble recovery yards (which, according to ESPN were only 9 yards...I didn't see the game). So, in fractional standard scoring, Gore should have 17.7 points. 83 rush yards plus 24 receiving yards = 11.7 points. Then tack on 6 more for the recovery TD. Unfortunately, he won't get any yards because it wasn't a carry or a reception, nor was it a return (there was no kick). No one ever gets yards/points for picking up a fumble and running with it, at least not in a standard scoring league.
In general, anytime a player scores a touchdown in a standard scoring league, they get 6 points. Whether it's on a rushing carry, reception, kick return, fumble recovery, etc, it doesn't matter; a touchdown = 6 points always. Hope that helps.