Disiullusionment or Hope?

My dad passed away on November 16, 2010 at 10:15 PM. One thing which has come into mind since then is what now? I decided even before he left his earthly body that I knew a few things. First, I know there is an afterlife. Second, I know there is a heaven and a hell in that afterlife, and that Purgatory is a step before heaven and all souls in Purgatory WILL be in heaven. Third, Jesus died so that humans may be with Him in eternal happiness in heaven. Fourth, there is a communion of saints in heaven made up of the souls of the men and women who are with God eternally in his Kingdom. Fifth, as a consequence of the fourth point, all souls in heaven who are with God forever are also with each other forever, so anyone who is in heaven will always be with God and also every other saint in heaven.
I knew and know those things. It is by the gifts of faith and hope that I know them, and these gifts I cherish and will cherish for the rest of my life here on earth, until I no longer need them.
One thing that I can never possibly know while I remain in this earthly life is the particular destiny of the soul of my dad. I know his soul is somewhere, living on. But, I feel almost entirely certain that if he is not already in heaven, in the communion of saints, he is in Purgatory, on his way to heaven. Of this I feel more certain than anything I have ever felt about before without being able to know for sure. I pray for him everyday, but I do not think he needs it because I think he is probably already in heaven.
My dad lived a very good life. In fact, he is the best, holiest, and greatest person I ever knew personally. Also, he was forgiven of his sins, via the sacraments of Annointing of the Sick and Reconciliation, shortly before his death, the final time when he was in a comatose state and could not conceivably committ any sins.
Because of everything I have written in this post so far, combined with the fact that my dad was and is my best friend, I desire more than anything I have ever desired to go home to heaven to be with my dad. Before I do that, however, I know I must be like Christ in as many ways as I can. I want to be just like my dad and to do what he would want me to do, which is be like Jesus. I know I cannot simply leave this life: it is not my place to decide when I will begin my eternal life. Thus, I must, for God and my dad, do my best to be the best person I can be in this earthly life.
This leads me to the division between disillusionment and hope. Knowing all that I know, should I just give up on this world? Surely, I am focused no longer on this world. My eyes are set firmly on heaven, where my dad lives or at least will live soon I believe. That is where I want to be for the rest of eternity. There, I will be with dad again, and we two best buddies can be re-united, and we will never have to leave each other again. Even better, we will, together, be with all of our loved ones and with God who is all good. I admit this is what drives every movement, every breath, every heartbeat, every ounce of strength used by me.
But, back to my question, should I give up on the earthly, non-eternal world? St. Augustine wrote about the "two cities", the City of Man and the City of God. My goal is essentially the City of God, and this earthly life is the City of Man. The City of Man will fall. It is as certain to come to an end as all living things on earth. The City of God is not only eternal but is also characterized by perfection, happiness, and the complete absence of suffering.
But I know that I cannot become totally disillusioned with this world. Although I consider myself to be in this world, but not of this world, to be a pilgrim who is merely passing through to a better place, I know that while I am in this world and while I am passing through, I must be good. I must work for the good. It is what God wants, it is what my dad would and does still want of me.
And so, armed with the constant guidance of God and perpetual prayers of Our Lady, all the angels, all the saints, and of course my best friend, my dad, I go forth to be the best pilgrim I can be, to bring to this earth in as many ways as I can the very Kingdom of God toward which I journey. With the Lord as my light and my dad ever by my side, how can I fail?
I cannot. I shall not. And for this, I say now and will say for all time, Glory to God in the highest. And while I'm here on earth, I say peace to His people on earth.