Just an attempt at being more specific on the window:
3:18 pm - MP seen on video in car in front of Dale's condo.
3:22 pm - MP parks, gets kids out of car, and enters Dales condo.
(something happens)
3:55 pm - Dale begins to pack up kids to go to parents house.
4:00 pm - Dale leaves towards parents house as he would need 30 minutes to get there
4:30 pm - Dale arrives at parents house as per witness.
As for the "something happens", if Dale did something, then everything would be likely to have occurred in this 33 minutes. If you were to believe Dale somewhat then Dale would have a relatively unexplained time between 3:32 pm and 3:55 pm, about 23 minutes.
The only way that Dale could have committed the crime, IMO, is that someone else was involved from the beginning at Dale's condo and that specific person is his mother, father, or both. I don't see Dale as the type of person to have such loyal friends that would cover up a dead body for him.
The extra person would allow him a much larger window obviously, and it could have been his mother driving Dale's car to her house with the kids.
I don't see him committing the crime, cleaning up, moving the H3 into the garage, etc. in less than 33 minutes. Not completely impossible, but difficult to see. And then you would have the situation with leaving incriminating evidence at his condo for at least an hour.