Without Excuse

As for those who have NOT been exposed to the written laws of the Old Testament and the New Testament (like those on some remote island or village untouched by apostles or prophets or missionaries), does this mean that those people are not held accountable or condemned for what they don't know? NO. Paul argues in Romans 1-2 that essentially people who are not exposed to the written law still have a law that's ingrained in them, that is "written on their hearts" by God, and they know whether they are doing wrong by their conscience (Romans 2:14). So these people who aren't exposed to and have never heard of the Bible, still have a law, which exposes their sin and therefore condemns them, because the wages of sin is death. So these people are without excuse... they  are not exempt from the law and the consequences of the law (sin and death). But even if these people follow this law written on their hearts, that is not going to get them saved. Furthermore, Romans 1:18-20 says that God revealed Himself plainly to people (including people who've never heard of the Bible), by showing Himself through creation... so nobody can give the excuse that they never knew about God. 

So how are these isolated people saved? In the same way as the people of the OT and people today... through faith in God's revelations of truth to them and if they have faith in these revelations of God's truth. It's not inconceivable that God could and would reveal Himself and His truth to some remote people and show them all the truths that He's shown to people throughout history (see the previous post for more details and Biblical support of what God revealed to different people from the past).