While I don't disagree that God is not restricted, the only way to salvation starts by hearing the Word of God (Romans 10:17).
That "Word of God", however, is not restricted to the Bible. Remember, Paul says that even the Gentiles possessed a law written on their hearts, even though they didn't have the written law. Thus, the Spirit is able to "speak" to even the pagans. However, this does not do away with the Church. This merely means that God can prepare man to receive the fullness of the Gospel, or He can give "enough" grace to the man whom He sees will not ever hear the formal Word of God as preached by a missionary - for example, those who live from faith to faith in God and were an Incan Indian living in 1200 AD - before Catholic missionaries ever reached them.
Regards