"Patrol 19" is a who (person or group) not a location. Patrol 19 has information about this, whether they are aware they do, or not. And is probably LE or related agency (think search patrol) and oh by the way, your box is full again.
I can't personally speak to 1forevry1's dream, but IMHO if her first instinct was an old wood barn, I'd stick with it, and dirt floor would for me reinforce that feeling. Barn, outbuilding of some sort.
To me it sounds like an old painted sign. Whether road sign, house sign or advertising sign or who knows what kind of sign. With paint beginning to peel. But that's just my interpretation of her dream. Would love to know more about it, and heck yes 1forevry1, how about a little Vulcan mind meld with that child of yours (joking, joking!!!). Whatever gets it out her of with no emotional scarring, eh?
$64,000 question would be where IS that old B&W sign and old barn? Is Rachael there, or was she, and is nearby?
Did she leave Moscow alive, but perhaps drugged, if they went to the Plantation or someplace else with alcohol and he spiked her drink?
As with all these cases, far more questions than answers. And a person missing who shouldn't be.