..... if we are going to go to Heaven, then why is the New Jerusalem coming down here?
Yes I have wondered at the language. But people are saying they are going to heaven, in the sense they are not currently in heaven so it is elsewhere.
The pictures given are hints, a new heaven and earth, a city without a place, God dwelling with man.
If you are going to be with God, put simply you will be shown, put in the place.
If not you will be put somewhere else. There is no mention of choice or ambling about and getting lost, so I think the actual location will be irrelevant.