I would definitely start Gore over both Kevin Smith and Jonathan Stewart. Would probably start McGahee too (so Bush, McGahee, and Gore as your RBs). Unless you're a huge underdog, I would not start Kevin Smith.
the Rb's facing the best match-ups are Stewart, McGahee and Smith. Smith's last game was against Car. The worst D against the run. Avoid him. GB is 10th against the run. I would play Stewart against Ind, Gore against Bal and McGahee against Sd. I would also sit Welker in place of Laurent Robinson. Teams have all learned how to slow down Welker. everything else is fine.