Well I believe that heaven is a definite place, outside of the universe. But I also believe that, when the prophecies of Revelation come to pass, a new earth - similar to the garden of Eden, will be established, that people will be able to freely travel back and forth to, from heaven.
Heaven is just too much for us to comprehend, since your flesh dies on earth so do all you senses, I believe it will be just an unending feeling of joy. but as i said cant comprehend. it would be like an ant understanding everything about humans. Dont know till we get there.
I honestly think that Christians have a hard time imagining heaven. Most of their imaginings are devoted to conjuring up visions of hell. Heaven is sort of,... well,... like,... okay.