That was firkin AWESOME, love the wood rails and.  Seeing some pins that I have in my own collection is always rewarding.
What is the background on this collection?

A guy on pinside put out the word that he was after some fairly hard to find low production number titles.

One of them was Mystery Castle by Alvin G (500 units) which he picked up from the Pinball Ranch shown in the vid at the 5:30 mark.

The owner allowed him to film the inside of the converted barn.

Apparently this vid is only a small portion of the total number. There were well over 1000 pins in total.