So I contacted my friend. Here are the answers to your questions from a wonderful mother, wife, and friend who has been in the church her whole life.
1. What is heaven? Heaven is where God dwells. It is our eternal home, we know there are many mansions in heaven John 14:2. There are three degrees of glory (Corinthians 15:40-42), we will be judged by Christ after His second coming and be assigned to a kingdom (telestial, terrestrial, & celestial), this will be determined by how we lived our mortal life. We are eternally Christ's children,(1 John 5:11-13) he ransomed us, we owe him our mortal lives by forsaking the world. If we really want to know answers to our questions we ask him!!! He will tell us! 1 John 5:14-15
2. Who goes there? I believe that it is what's going on here on earth. Missionary work, the Lord's work, his Gospel. In heaven people are taught Christ's gospel, to follow and know him, become like him, and become one with Him. So the work is teaching and learning and we are all at different levels of understanding and obedience.
3. How does one get to "heaven"? I believe the spirit world is all around us. There are both good and evil spirits working with us or against us in our quest to endure to the end in mortality. If we want to live with God we must rely totally on Christ to get us there he is the gatekeeper! We must listen for and follow promptings of the Holy Ghost exactly, it is the voice of God. If one repents of all sins they are forgiven through the power of His Atonement, even of murder; (denying the Holy Ghost is the only son that is not forgivable. Mark 3:28-30.) We will earn our reward based on our life lived here...2 Corinthians 5:7
So that's my take. ;-)