ponzy, I think you are getting your mindset on the right track.
Is there any way you can lighten your pack? 20 lbs is an awful lot for a day hike.
Leaving the camera behind is good. Now if you can understand that you don't need to carry water until you reach trail camp, that will make your pack a lot lighter, too. Some people carry a filter or steri-pen. Others (like me) just dip and drink. The water has never been found to have enough bacteria or impurities to hurt anyone.
My method:
