This is a helpful way to understand the book of Revelation. Of course, John was not vacationing on a Mediterranean beach. He was in exile, having been arrested and imprisoned by the Roman authorities. But he had even more reason to write home than a tourist. He was a loving pastor, a spiritual father to a number of churches - it was them to whom he wrote. Some of his fellow believers had seen him arrested in the wave of persecution that was sweeping the area. They had seen him dragged off and had no idea where he was, no idea whether he was dead or alive.
Of course he wanted to get a message to them. They were worried for him, afraid for their own lives as the persecution deepened, confused about the Gospel that had seemed so true when they had been singing each week that "Jesus is Lord", but now it seemed that "Caesar is Lord" was closer to the mark.The mark of the beast. Every spiritual father, every pastor, would want to write home in such circumstances. And the Lord appeared to him: the divine instruction to write lined up with the desire of his own heart, and the divine revelation gave him the content of what to write. The result was what we are calling his postcard from Patmos.
There are many unhelpful ways to view the book of Revelation. It is not, for example, an early attempt at Science Fiction. This is not a first century equivalent to Star Wars. This is not a kind of Dungeons and Dragons. Neither is it a Mayan prediction about the end of the world in 2012, nor a forerunner of the Nostradamus prophecies. John tells us he was interested in the immediately unfolding scenario his flock was facing (Rev 1:1), as any good Shepherd would be.
What is wonderful for us is that John posted his message so that we could all look over the shoulders of the churches to whom he wrote, and read their mail. It's not in a sealed envelope but in an open book. It's as if he posted it on the web for the world to see. It's gone viral as millions have read his words and viewed his pictures. It's not speculations about the future so much as it's a father's heart for spiritual sons and daughters having a really hard time. Which is why its message is timeless and as relevant today as ever.
The Romans had many terrible faults. But they did invent a very efficient world-wide postal system. I'm glad John's postcard from Patmos did not get lost in the mail!