Karen - routines do work quite well in our house hold. I think it's the predictability that one thing (brushing teeth) will lead to another ( eg bed time), so there are set expectations and no surprises.
And I hear you totally on the older two fighting and taking up more of your time. Last week I started giving the eldest (3.5 yrs) a warning then put her in time out if the behavior continued - I tell ya if I had have realized what a turn around that would make I would have started using time outs much earlier on instead of putting up with the naughty behavior.