Secondly, why would she tell everyone to pray the rosary everyday? Shouldn't she be leading them to her Son? Shouldn't she be giving them the gospel of the grace of God? We are told, in God's Word, to preach His word. To be ambassadors for Christ, to be reconciled to God by the finished work of Christ, that God made Christ to be sin for us, who knew no sin; that we might be made the righteousness of God in him. We are not ambassadors for Mary, nor are we given instructions by God to pray a rosary for ANYTHING.
You also stated God didn't give us instructions to pray the Rosary. You couldn't be more wrong. God tells us to pray often. He doesn't tell us not to pray the Rosary. Mary did tell us to pray the Rosary and I don't think God would have allowed her to say that (or even make the visitations) if He did not permit it.