I would play small (1 or two table) S&G's before I hit MTT's. That will get you comfortable with the intricacies of endgame play. It would be tragic if you got deep into an MTT but found yourself ill equipped for proper short handed, short stacked play, as that's where the real money
is at. The difference between 1st and 5th in an MTT is usually pretty big.
As far as playing ring games and tournaments together, that's fine as long as you can seperate the two. Cash games and tournaments have different strategies.
When I started I only played one or the other. Well, I'd play something different on occasion to break the monotony, but I found it easier to just concentrate on ring games, then just concentrate on tournaments.