Protestant authors that are gateways to Orthodoxy

The Protestant authors that are gateways to Orthodoxy are largely English Anglican authors and still preserve something of the historical church.

Two good ones are NT Wright and CS Lewis. 

Wright and the New Perspective of Paul (NPP) have caused a stir in the Reformed world. He's taken on the Reformed view of justification. The NPP starts with a more critical view of the world of the first century Hebrews. Wright's four volume series, "Christian Origins and the Question of God", (projected to be six volumes) is a masterpiece of writing.

CS Lewis is widely read and enjoyed from his Narnia books. Some want to read more and discover his other deep writings.

Once you start down that path, it's hard to look back.