I have constructed a brief rough schematic of Adams motives, here it is:
It all comes down to his mental disorders, isolation, loss of reality and seeing the world as meaningless and hurtful, he probably saw children as being domesticated by society and he probably wanted life more simple just like chimp society as he saw society as too stupid, complex, judging and ignorant of nature,thus possibly killing these children so they didn't have to suffer like he had (possibility). i believe he was very disturbed from the suffering he had given to himself through purposeful starvation and dehydration aswell as sleep deprivation which caused him to have screaming face hallucinations around 5:00 Am in the morning and when he was very fatigued, i believe he started to plan around late 2010 - July 2011 after seeing the mass scale and brutality of Anders Breivik and the largest mass murder by a single gunman in history, i believe during that year he descended into oblivion and his mind was irreversibly disturbed, he was intelligent so i believe the reason he targeted Sandy Hook Elementary was because:
It was close to his house
He knew the layout since he formerly went there
The shock factor and lack of resistance (easier targets = higher death toll)
and cause it was a psychologically meaningful place to him where he was a child and probably enjoyed life better then, he grew up there so he wanted to die there
I also believe he had St Rose in his sights as his GPS records showed that he took multiple trips to and past the school aswell as Sandy Hook.
In the end i believe he saw no future for himself and hated the pain that reality caused him which made him resort to a fantasy world where he had many disturbing psychological experiences (hallucinations from sleep deprivation/dehydration/starvation, virtual violence, videos of children shows and children being happy and playing with their friends, paranoia, total sensory isolation (pitch black rooms with no sunlight and only a screen producing light, Psychological episodes in the early morning including crying in toilet and possibly the reason he hit his head a few days before the massacre.
in conclusion he was Disturbed, Suffering,hopeless for a future and thought the only way out was to kill himself and due to his obsession with mass murder, he undoubtedly wanted to commit a cruel massacre with a major kill count that would leave him with the legacy of one of the most evil mass murderers of all time, he was obsessive over mass murder and knew the exact factors that would make his attack devastating and what firearms to use to cause max casualties, he was probably envisioning himself at the top of his spreadsheet.
I'll probably re evaluate my thought of his motives over time and will refine it with the more data on Adam i find, hopefully we see more info on Newtown and Adam in the future but unfortunately i believe we wont. There will always be mysteries unsolved.
What do you guys think? anything you feel i missed or need to correct?