Craig Blomberg's The Historical Reliability of John's Gospel examines John's Gospel verse by verse and identifies an abundance of historical details and facts.
2. Given the early Christian tendency towards asceticism, the wine miracle is an unlikely invention [2:8].
3. Archaeology confirms the proper place of Jacob's Well [4:6].
4. Josephus [Wars of the Jews 2.232] confirms there was significant hostility between Jews and Samaritans during Jesus' time [4:9].
5. "Come down" accurately describes the topography of western Galilee. [There's a significant elevation drop from Cana to Capernaum.] [4:46, 49, 51].
6. "Went up" accurately describes the ascent to Jerusalem [5:1].
7. Archaeology confirms the proper location of Bethesda [5:2]. [Excavations between 1914 and 1938 uncovered that pool and found it to be just as John described it. Since that structure did not exist after the Romans destroyed the city in A.D. 70, it's unlikely any later non-eyewitness could have described it in such vivid detail. Moreover, John says that this structure "is in Jerusalem," implying that he's writing before 70].
8. Jesus' own testimony being invalid without the Father is an unlikely Christian invention [5:31]; a later redactor would be eager to highlight Jesus' divinity and would probably make his witness self-authenticating.
9. The crowds wanting to make Jesus king reflects the well-known nationalist fervor of early first-century Israel [6:15].