Your questions are not new ones. I know that it can be frustrating and indeed we could drive ourselves mad if we dwell in them... because we simply can't know the answer. I think that is where humility comes into play. Some things we just have to let go and realize that our ability to understand and our access to certain knowledge is limited by virtue of our being in this flesh... its limiting... but we put our faith in Him and trust that even if we can't see the plan in its fullness, He knows better than we... just like a tree in the forest can't see the greatness of the forest and all that it provides... it just has to stay rooted and do its part as it is designed.

My theory is this, though, as it relates to your question, but its merely the best I can do in my own thinking, and could be totally off... but I understand the need to have some grasp... so here is what I think, however unscholarly it might be.

If God were to have just created us in Heaven to love Him and have relationship with Him, would we have had a choice? Here, in this flesh, we are given the opportunity to accept or reject Him... if my husband didn't have the option to NOT love me, how would I find his love to be sincere... I wouldn't. A sincere and fulfilling relationship is based on choosing... I choose God. If I didn't have an alternative choice, no "b" option, if you will... then what grounds would there be for my relationship with Him to be a two way relationship?

God created the angels in Heaven... perhaps it would help your intellectual investigation to examine the differences between angels and humans. Are angels created in His likeness? Do angels have free will? satan was an angel who fell from grace, and with him a third of the angels were cast out of heaven... to where? here! Maybe we are here as a part of a plan to continue to execute Gods wrath on satan... satan is no match for God, and he knows it. he is the father of lies, and here, born in iniquity, yet with the offer to be saved by grace, we have an opportunity, an honor and priveledge, and i believe, an obligation to declare spiritual warfare against the hosts of wickedness. When we arm ourselves with the knowledge of God and the true weapons of our warfare, we then realize that the enemy is a defeated foe..

But it is the enemy who is always trying to take us OFF of the track you speak of 'trying to stay on'... and if we try to stay on track in our own power and knowledge and wisdom, we fail, being born in iniquity. But when we receive the power that He offers us by His Spirit, we surrender to His will over our lives rather than our own, we make HIM King of kings and Lord of lords... then we know that it is not WE who are keeping ourselves on track, but Him working in us... the best we can do in our own power and strength, and what we MUST do, because it is the one true requirement on our end is to SURRENDER. If we do not surrender then we limit what the Holy Spirit can do in and through us.

Don't condemn yourself for "slipping" further away... just keep rebuking the thoughts that satan wants to whisper in your ear, telling you that you aren't doing enough, that you can't do receive what God has for you for whatever reason, that your efforts fail and you are unworthy... cast down all those imaginings which exalt themselves against the knowledge of God, and bring all thoughts into submission to Christ.

I remember when I was in school, certain things that I had to do seemed pointless... and it wasn't until I was older that I was able to see that there was wisdom which I couldn't see. When it comes to God, there is always wisdom beyond what we can see in our present fleshly condition. When my daughter is demonstrating obedience, she does what she is told without an explanation. If she demands an explanation for WHY she must do it, then she is not submitting to my authority. Sometimes when mom says "STOP" you just have to stop first, and then after you have obeyed without question, the reason "why" might make itself evident in its own time. You never know when GOD yells STOP (or GO!)... if the reason will be quickly evident. But when I yell "Stop" to my daughter, she had better stop, because it just might be a moment where disobedience could cost her her very life. I have no reason to believe it is any different with God.