For WR's start Bruce and Brown, no question. You're looking pretty good there.
You have an outstanding RB in Alexander, but after that the drop-off is staggering. Alstott, as a free agent, is still better than sixty percent of your running backs, and only a few draft slots below Stewart imho.
For now, grab Alstott, and I would be looking for some sleeper backs to add to the roster. Who is available will vary from league to league but you might consider Foster, Duckett, James Allen, and Hambrick, or maybe the backup to Edge if you anticipate he won't hold up.
You can also get some mileage out of a receiving back like Larry Centers or Kevin Faulk if all the sleepers are gone. I think there will be a bit of a dropoff (at least in receiving yards) for Centers, because Bledsoe locks in on a receiver and doesn't look until the last second to dump off a pass. Faulk, on the other hand, could easily see an increase in numbers, as the Pats scramble to hold onto their position atop the AFC. Facing tougher opponents this year, Brady will probably rely on tight ends and dump offs to the RBs, and A. Smith will probably be kept rested and healthy for when he's needed most, all pointing towards more yards and scoring opportunites for Kevin Faulk.