When Jesus said heaven is not a place he meant only it is not part of spacetime.
In the following section He talks about this. Notice the section is called “beyond the body”, not staying in the body.
“VI. Beyond the Body
1 There is nothing outside you. That is what you must ultimately learn, for it is the realization that the Kingdom of Heaven is restored to you. For God created only this, and He did not depart from it nor leave it separate from Himself. The Kingdom of Heaven is the dwelling place of the Son of God, who left not his Father and dwells not apart from Him. Heaven is not a place nor a condition. It is merely an awareness of perfect Oneness, and the knowledge that there is nothing else; nothing outside this Oneness, and nothing else within.”
Anything outside of heaven, which means this universe of illusions, is not part of Heaven, is not real, and does not exist. There is no world. And “there is no life outside of heaven” meaning anything outside heaven (Earth) is not life.
Also, ask yourself this. Where is Jesus? Apparently he is not in a body. He left bodies permanently 2000 years ago. So where is he? You cannot experience heaven while being in a body still. The body has to be disappeared in the overcoming of the illusion of death, before you can be freed of the limitations that the body places on awareness.
Many times Jesus states “in Heaven.”
Jesus is in heaven. He is not in a body or in this universe. ACIM was comminicated to Helen through channeling from another dimension.
Being in the reflection of heaven, which is the face of Christ, in this world, is not being in heaven. Heaven is an awareness ONLY of God as real. Abstract, pure, holy and eternal. ”Heaven and Earth are opposite in every way” tells us if you are “in Earth”you are not in Heaven. Otherwise God created this world, which is bullshit.
”God is in everything I see”applies only to seeing the face of Christ in this fictional world, which is only preparation for the transition to heaven. It does NOT mean God is in this world or that God is lurking behind its forms. Who can be at peace with death and destruction, or accuse God of creating such a cruel world, when death is a sign of hatred? God is love, not hate, and eternal life does not mean bodies that suffer and die.
Read the lesson “no one can fail who seeks to reach the truth”. It takes you BEYOND even the real world, beyond true perception, beyond the face of Christ, beyond the forgiven world, escorted by Angels to Heaven. And Jesus says He can take you to Heaven any time. He wouldn’t exactly have anywhere to take you if being in the world meant you were there already.
Heaven is not Earth. Earth is not real and does not exist.
”Heaven remains your one alternative to this strange world you made and all its ways; its shifting patterns and uncertain goals, its painful pleasures and its tragic joys. God made no contradictions. What denies its own existence and attacks itself is not of Him. He did not make two minds, with Heaven as the glad effect of one, and earth the other's sorry outcome which is Heaven's opposite in every way.
God does not suffer conflict. Nor is His creation split in two. How could it be His Son could be in hell, when God Himself established him in Heaven? Could he lose what the Eternal Will has given him to be his home forever? Let us not try longer to impose an alien will upon God's single purpose. He is here because He wills to be, and what He wills is present now, beyond the reach of time.”
”You cannot fail today. There walks with you the Spirit Heaven sent you, that you might approach this door some day, and through His aid slip effortlessly past it, to the light.”