|Henri Lindegaard, Of Earth and of Heaven|
Heaven isn't too far away from the person who has a vision from God, because that person sees the stuff of heaven here and now in this age. This is best illustrated in Jesus' conversation with a well-schooled Jewish religious teacher named Nicodemus. (You can read the whole thing, with the biblical author's commentary, in John 3:1-21.)
Nicodemus recognized that Jesus had come from God in some sense and that God was with him because of the miracles he was doing. But while Nicodemus was still warming up for his question for Jesus, Jesus interrupts him with, "I tell you the solemn truth, unless a person is born from above, he cannot see the kingdom of God."
A couple things in this sentence are worth explaining. First, Jesus is talking about the kingdom of God, which, as I've explained briefly here, is God's authority to rule his world as king. It is his royal government. That government is real now, but it is obscured by the flawed (at best) and defiantly rebellious (at worst) governments that we see and live under now, which in turn are silently and invisibly manipulated by the Evil One. When Jesus returns, the invisible government of God will become visible and permanently up-end all other governments. Nevertheless, even now God's government is visible to and among all those who acknowledge him as king and obey him as such.
Second, the people who do see God's kingship even now and respond accordingly are people who are "born from above." The Greek word translated "from above" might best be understood as "from the top." "From the top" can have to do with time, as in "from the beginning" or "once again"—musicians at once recognize the direction, "Take it from the top" to mean, "Go back to the beginning of the piece and play it again." So "born from the top" has frequently been rendered "born again." As Nicodemus' response indicates, this might have been what he thought Jesus meant. But it is more likely that Jesus intended "born from the top" to mean "born from above," from heaven. Heaven is the spiritual realm where God's royalty is plain right now. People who are born from there, and only they, see God's royalty plainly on earth.
Jesus explains that the way people are born from heaven is to be born by the Spirit of God. Humans come into being physically alive and spiritually dead. Just as it is absurd that a person would perceive the physical realm before their body was conceived, so also only by God fathering us spiritually by the Holy Spirit do we perceive the spiritual order in which God is king.
For those who have been fathered and born like this—evidenced by their faith in Jesus alone as the one who made possible their birth—heaven is not foreign territory. In fact, somehow, even though our physical eyes cannot see it, we are already there even as we dwell with our bodies here (cf. Eph. 2:1-10 for all this). Likewise, we can see the activity of heaven here on earth. We can imperfectly recognize fellow residents of heaven when we meet them. We not only see the effects on earth of the exertion of the power of heaven, but we recognize the source.
When we articulate our vision, it will necessarily entail concepts and evidences that make sense to earthly people, because we are earthly people with a vision of what God intends to do through us on earth. But if there is not some heavenly dimension to the vision, some way that it simply does not make sense to people who have not been "born from above," then it does not come from above itself and is not a true vision at all.