Agreed to find the 3 whatevers. Get to the room that has the benches. Try both corridors off the sides. Get to an iron gate and there is no option to open it or any devices nearby to open it so I cannot go any further into rest of Valthune.

UncleMike

are you in the catacombs?

I just did that one last night. There is one place where the release is not a chain but a handle to the left of a gate. It has the look of the one’s in the room with 3 handle releases in the middle of the room but on the wall and harder to see.

Stare at the iron gate, turn 180 degrees, look for a shoulder height push/pull switch to open a hidden section, and prepare to die or get a nice sword and board. If you can get lucky jumping in the chamber with the benches, this will be the second nice board from this barrow.