Here's one example I use in the 2nd chapter of the book that points to both the literal existence of the seven churches, and further evidence of the writing of the letters before 70 AD:
{14} ~'But I have a few things against you, because you have there some who hold the teaching of Balaam, who kept teaching Balak to put a stumbling block before the sons of Israel,
to eat things sacrificed to idols and to commit acts of immorality. {15} ~'So you also have some who in the same way hold the teaching of the Nicolaitans.
Revelation 2:14-15 (NASB)
As I point out in the PDF file in the OP, the issues of eating meat offered to idols and immorality were nothing new to the apostles. Paul dealt with these same issues in Jerusalem before he was seized (Acts 21) and in his letters to the Romans (14) and 1 Corinthians (8,10).
{25} "But concerning the Gentiles who have believed, we wrote, having decided that
they should abstain from meat sacrificed to idols and from blood and from what is strangled and from fornication."
Acts 21:25 (NASB)
There are other examples (that I haven't put in the PDF, desiring to keep it short):
- The problems of false apostleship (Rev. 2:2, 2 Cor. 11:13),
- Backsliding churches (Rev. 2:4-5, 1 Cor. 10, Gal. 1:6)
- Tribulation of the Church (Rev. 2:10, Acts 14:21-22, Rom.5:3-4, 12:12, 1 Thess. 1:6)
Here's how I summarized the issue of eating meat sacrificed to idols in the PDF: