The sniper set-up and weapons cache with automatic weapons was clearly a thought-out attack. Of course, he had two airplanes, so he could have done even worse damage had he not been an ammosexual.
Is it possible that the ammonium nitrate might have been to put into one of his planes? (my conjecture) Apparently he had no detonators but a mixture of diesel fuel and fertilizer would almost certainly detonate under the force of impact of a plane diving into a crowd.
I have seen reports that his pilots license was expired due to not having a current medical clearance, but that would not have stopped him.
Yes, he was indeed unbalanced, but was clearly fogged out on ammosexuality and not just mass destruction as he had other, worse weapons at his disposal. Puzzling.