Are we in God's dream?  Are we in an aware conscious, a very creative daydream that God will snap out of or a deep REM sleep?  In addition, will any of the content of God's dream somehow make it back to God's reality when God awakes?  Does God's dreaming make things reality?  Or will God simply leave all that was created in the dream-state?  Is it appropriate to assign human characteristics to God - like dreams?  What kind of God would we have and how could we describe this God if we did not?
If God is in a dream-state of any sort, who is going to wake God?  Observing God as the perfect being, God's dream would be perfect - in depth, width, height, space, time, and relationship.  Either way, whether God is dreaming or conscious, all that God does is perfect.  So, is God dreaming or is God awake?

They say that only a fraction of brain power is used while awake.  So, imagine the possibilities harnassable in "dreamland".  This truly applies to us - now.  However, how about a dreaming God?  Who can know the mind of God?  Who can fathom God's thoughts?  We can't hook God up to an EEG machine.  That would probably result in either weird findings or no findings at all.

Will heaven be our wake-up call?  Is that existence our true form?  Are we "sleepwalking" in this world and death wakes us?

I think all of this is real.  Life, death, and the afterlife are real.  I think heaven will be a "wake-up call" of sorts, but not from a dream-state.  It will be an awakening to all that has been on the other side of "life's curtain" and all the potential we can become.  I think that the heavenly, perfected form is the existence we were intended to have and will be at least the form we are restored to by Christ at the Rapture.  I also think/believe that we may evolve in different ways beyond that point.  Are we "sleepwalking" in this world?  Some sure look like it and others I feel are - yes - flat out, sleepwalking through life.  But, concerning death and/or the Rapture as the agent of waking, I would say for the unbeliever in Christ, this proves to be the biggest wake-up call of all time.  We all can wake up long before then though.  When an individual makes the decision to accept Jesus as their personal Master of their life and Savior over their relationship with God, then is when the WAKE-UP really happens, in my book.

Are we in God's dream?  No.  To dream would imply, as above, sleep and God does not sleep.
"...he who watches over you will not slumber;" (Psalm 121:3)  Thank God that He does not sleep, He doesn't slumber, He watches me both night and day.   "For the eyes of the LORD range throughout the earth to strengthen those whose hearts are fully committed to him." (2 Chronicles 16:9)  And His brainpower is Supreme just the way it is.  "For my thoughts are not your thoughts, neither are your ways my ways," declares the LORD.  "As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts." (Isaiah 55:8-9) 

Aren't you glad it's not all in your head?  Creation, life, history, and The Plan have always been in His head!  Just a perfectly alert mind of God, not a sleeping and dreaming God.  And then the thought and Word became Flesh (Jesus), but that is another story for another day.  ;)