"Perhaps God really is so good that he's made a way for everyone, or perhaps he only saves those who call on him."

The first thing I'd like to point out is that the two ideas in your above statement are not mutually exclusive. It’s only those that call on their Father that are ‘saved’. We believe that God has made a way (Christ) for everyone that calls on Him, and we believe that eventually all will do so.

"I do not know, but what I do know is that I'll continue to preach the Gospel of grace."

You should! Please continue to preach the Gospel of Grace! The gospel is the means by which people are led to call out for a savior! It’s the good news that brings someone to the Father.

The only issue I see in what you’ve stated is that you seem to be under the impression that death is the end. And it isn’t. If Jeffery Dahmer were to have accepted Christ and repented on his death bed you would have no issue with him being in heaven. Does God stop loving Jeffery Dahmer at his death? Does Gods desire for the heart and soul of Jeffery Dahmer turn to everlasting hate upon death? How can such a change take place in God? No, I believe that God is ever pursuant—even in the case of the Jeffery Dahmer’s of the world. Death is no escape from Gods Grace and it certainly can’t be the end of it.