New poster here, but I wanted to tie up ideas I've been having about the significance of Dougie's involvement with the Silver Mustang Casino.  I'll start with some observations and then go to some theories:

1)  There is a significant degree of similarity between the idea of a "Silver Mustang" and the "Pale Horse" seen elsewhere in the series.  Probable connection.

2)  Dougie, with help from Mike who forces the scribbling all over the case files, effectively saves the Mitchum Brothers, owners of the Silver Mustang. 

3)  After the Mr. Jackpots scene, the pit boss named "Burns" gets beaten/fired. At this point, we hadn't seen the charred woodsmen yet. The fact that the pit boss's name was "Burns" could be some foreshadowing of the fact that Dougie's involvement with the Silver Mustang could help represent a victory over the evil woodsmen spirits. 

4)  We know that the Pale Horse has made two other appearances in The Return during Coop's expulsion from the lodge and also the whinnying heard at the end of he episode in the desert.

5)  The Lincoln-looking woodsman said, "The horse is the white of the eyes, and dark within". 

6)  Sarah Palmer has seen the horse on two occasions in the original series, and currently there's been some strange stuff going on at the Palmer house.

Now, here are some of my thoughts.  Wikipedia references the mythology of the white horse as being unusually heroic.  I think Sarah witnessed the pale horse spirit back when Leland killed Laura as a sign that she had the power to stop the abuse from happening and being the hero.  However, she is living with the guilt of not "getting on the horse" and saving the day.  This may be her "albatross" of guilt.

We know the pale horse spirit is till around the black lodge in the return, and may be some nice indication about how Dougie's involvement in the Mitchum plot is an act of heroism. The Mitchums have definitely helped Dougie out in a big way, so maybe the Silver Mustang is a vehicle for Coop's revival.  This could be the start of a comeback against the woodsman/atomic mother, etc.