Here is a link to a photo of the "40 acres" backlot in 1965. The photo shows many different sets, including the Hogan's Heroes exterior set, which is in the top right corner of the backlot.
The Hogan's Heroes exterior set was on the southeast corner of Lucerne Avenue and Higuera Street in Culver City, California. Look at the top of the photo, and you will see the water tower that can be seen in the background of some scenes in Hogan's Heroes.
Here is a zoomed in and cropped photo of just the Hogan's Heroes exterior set:
In the lower left quarter of this photo, just past the white step van is the rear of the facade that was Klink's office. The steps up and the door are on the other side of the structure. That west side faced "Barracke 2", which was the building Hogan and his men "lived" in. Notice the fake snow painted on the roofs. Notice that the "barbed wire fences" ran only about 100 feet to each side of the "main gate".
Here is a fairly recent photo of the northwest corner of the former "40 acres" backlot where the Hogan's Heroes exterior set used to be located:
After comparing photos of the former exterior set to this image, my best guess is that the barracks used by Hogan and his men is just a few feet to the right of the yellow push pin image on the newer photo. The door Hogan and his men used was on the east side, the right side, in this photo. About 50 feet to the east of that barracks 2, (to the right in this photo), is where the facade of Klink's office building was.
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