You've got to go with the consistent back whos going to get the red zone carries no matter what. McGahee is that back even though Hightower is playing well. The Colts rush defense is horrible without Bob Sanders and Hightower has been performing well as of late. The thing is, McGahee has been destroying opposing teams in the red zone and they're playing the worst rush defense in the NFL. The Browns are giving up over 200+ yards per game on the ground, go with McGahee.
As far as Steve Smith or Roy Williams. I personally hate Williams with a passion and I consider him to be one of the most overrated WR's. In no way, shape, or form is he a #1 WR. Steve Smith on the other hand has been playing extremely well lately and it should continue. The only thing is the Giants are a rush offense first. Look at the recent stats of both Jacobs and Bradshaw, neither are anything of what they should be doing so sooner than later they will get the rush offense going which means limited catches for Smith. Smith isn't really a red zone threat but seeing how they're going up against a horrible pass defense he should net you at least 8+ points with a possible TD. Start with Williams but after Smith has a decent game, I'd try to get rid of both of them for a true #1 WR.
Start the Packers against the Rams. Woodson and Harris will get you a few picks and should hold the Rams below 13 points.