I've read this in a comment, these are my conclusions too after watching the final episodes:

"So, we learned that Judy is a tricky bitch. 

Cooper saved Laura from bring murdered that night. However, Judy stole Laura before she and Cooper could get back into the White Lodge. At that point, BOB had been destroyed prior to Cooper going back in time to save Laura. 

Because Judy took Laura on the way into the White Lodge, it means that Judy is still out there, and still active. Cooper re-emerges from the Black Lodge to meet Diane. At this point, reality is somewhat stable; BOB is still very much dead. 

However, when Diane and Cooper are in the car near the powerlines, and it's close to 430 miles, Diane clearly says, 'We might not be who we are now, once we go through.' Cooper and Diane go through and the timeline utterly shatters. 

Judy will do anything to protect herself, because Judy is Mother. Judy punching the picture of Laura was a direct result of anger and frustration at Cooper trying to pave over history and stop Laura's death - which he succeeded in doing. When Diane and Cooper cross over at the power lines, they emerge filling the shoes of Richard and Linda. We also have an occurrence of Diane seeing her Doppleganger. The ending timeline has been utterly screwed with, to the point that Laura doesn't recognize her name, and barely the name of her Mother. Laura's house isn't owned by Sarah; but it was sold to the present owners by the Chalfont's, who we know to be Black Lodge agents, who might very well be working for Mother. The biggest clue here is Dale pausing and saying loudly, 'What year is this?' to which, Laura has no answer. Saying 'what year is this' breaks the fabrication. Laura screams as she screamed in the Black Lodge, the house is flooded with a burst of electricity, and the reality is shattered; everything turns black. 

Dale went after the big game of trying to get Mother. It didn't work out too well.