I'd say a lot of how well your season will go depends on how much time Manning and MJD may or may not miss. Cassel should be fine as a back up and you got some pretty good RB depth. I like your WRs, if Smith can come back to being a top tier WR then you probably got him on a steal. Best of luck to you.
Decent team. Don't care much for Beanie Wells as your RB2 and am also concerned with S. Smith - getting old with a rookie QB spells trouble. I think you're a little thin for a 12 team league...