I will share my personal experience with meditation. I have been practicing for around 16 years. I used to practice hardcore, I have sat in Zazen for weeks at a time. Not only that I practiced even while at work, no matter what I was doing, for years without ceasing. But here was what I found out. What meditation shows you ultimatelty is how to hold your mind so that you are free of suffering. I found that even if you sit for three weeks concentrating your mind, you can get the same results just taking one step in mindfulness.
For instance, if you feel a feeling of joy in your heart, and if you are aware that you are feeling it, then you have already mastered meditation. Many people think you have to clear your mind and don't allow your mind to think. They struggle, and the practice is unpleasant for them. But in reality when you practice correctly there is no struggle and a calm joy pervades your heart. You find that you have a hint of a smile that cant be erased. It is the smile of non suffering. It arises all on it's own.
To meditate you don't need to do anything at all. You don't need to sit in the lotus posture, or chant sutras. All you do is take a breath and know you are taking it. You walk and know you are walking. You feel joy and know you are feeling joy. You feel sorrow and know you are feeling sorrow. It is just base awareness of this present moment. You can still have thoughts, you just don't allow yourself to get caught by them. You allow them to pass by like clouds in the sky.
If you have been feeling joy in your heart, and you know what state of mind brought about that joy and you continue that, then you are already a meditation master. :) As you stated in post #8. Also if you are able to be in a room for 24 hours and be at peace you may be Bodhidharma reincarnated, Lol. Bodhidharma was a monk who sat and faced a wall for 9 years.