Heaven consists in the perfection of Charity, in loving God for his own sake with perfect love and loving one another for God’s sake with perfect love. There are other perfections as well.
If I choose not to love God, then I cannot be in Heaven. Period. It is just not possible for me to love God perfectly (which is part of Heaven) unless I choose to love him. Love is an act of the will, and we have free will. It would make us less than human and incapable of love if God could “force us to be saved.”
There’s only one way to salvation: Christ. The Church is necessary for salvation because Christ is necessary for salvation. Anyone who is saved outside the visible boundaries of the Church is to that degree oriented to the Church and whatever grace they received was received through the Church.