|Annotated scan of the cover image of B2 The Keep on the Borderlands. Art by Jim Roslof.|
I've looked at the cover of B2 countless times. It was the first module I owned. But I don't recall ever noticing until yesterday that you can see at least two of the Caves of Chaos in the background of the cover painting (circles marked B and C). My eyes have always focused on the combat in the foreground, which (without thinking about it too much) I assumed was a random wilderness encounter with hobgoblins (the Monster Manual describes them as having bright red-orange faces and blue noses). I never really noticed those dark spots in the background. But now they look to me like they must be cave openings in the distance, and thus the combat is taking place right in the valley of the Caves of Chaos, which completely makes sense as an artistic choice for Jim Roslof's composition.
So which caves are they? The cave on the left is higher than the other as if they are on different contour lines as shown on the map. But since the hill overall seems to be sloping down to the left I would assume we are facing south. If so, the high hills in the distance would be south across the river (perhaps the peaks where the bandit camp is located). Caves J and K would roughly fit the pattern except the map shows them hidden in the trees. Caves D and E are to the left of Cave F (the hobgoblin cave), but are lower. So they are not easily placed.
Edit: I revised the annotated scan to show the cave locations suggested by paleologos.
A is the Kobold Lair (partially obscured), B and C are the two Orc Lairs, and G is the Shunned Cavern, hidden behind a stand of trees.