Catholicism is the one true faith in God, which traces its history to the beginning of time. That is to say that Catholicism is the faith that Yeshua (Jesus Christ) established as the complete and final manifestation of the Faith of Abraham. Every ‘Christian’ (Trinitarian) sect comes from the Catholic Church in one form or another. Those non-Trinitarian, or quasi-Christian, sects are branches of these groups. The Jews are our elder brothers in the faith being the first called and set aside for the Lord. Mohammedanism is a later Arab corruption of Hebrew and Christian religiosity.
So, if you are looking for the source of Trinitarian Christianity then yes, Catholicism is the one, true Church and all others, while containing elements of truth to varying degrees are truly Christian, though less perfect in nature than the original source – the one that He established.
Can and do non-Catholics go to heaven? I bet they do and I am grateful for that! Do Catholics go to hell? I bet some do and I am very sad over that. Can a non-Christian or even a non-monotheist (Jew or Mohammedan) make it to heaven? I bet they do and I am grateful for that.
Praying the rosary is not an essential element of the Faith and is not required for salvation. Neither is reading, reciting, or praying Scripture, which is what the rosary truly is. However, both are very, very beneficial and I recommend that everyone pray them.
A note of caution needs to be mentioned here. Namely that those who know full well, with their whole heart, mind and soul that the Catholic Church is the one, true Church and still rejects it… well I would not want to be him…