To me, the Giants game is key.
The Giants are the most beatable team on the Rams 2nd half schedule.
If they can get to 6-2 (and they should unless they're flat on Sunday), then they can probably go .500 the last 8 games and get a WC spot. Not for sure of course, but they would definitely be in the hunt.
Even if they didn't get a WC spot, a 10 win season would be amazing. Well beyond my prediction of 9-7 as the absolute ceiling.
The Garapallo Niners don't concern me too much because the Niners don't have a good offense and Garapallo is not going to learn an entire new offense on the fly in a few games. He'll be better than what they've had this year; but to come in cold at this point in the season to an entire new system is tough.