I’m just struck by how much bigger it is on the inside group than the rebadged Calumet/Rodenstock I had, which on top of everything else was an F 4.5 rather than an F8.
That's because it wasn't really designed for 4x5 cameras. It is easily a 5x7 lens, and possibly can just barely hit the corners of an 8x10 if you stop down far enough.
The 125mm W / NW / NWS / CM-W lenses are all much smaller and lighter and also have much smaller image circles. They also have much smaller rear element groups.
If you really want large movements, the 120 SW is the way to go. Most people don't need that kind of coverage for normal shooting, and as you've discovered, there are physical fit and geometry issues that can occur with the large lenses on smaller bodies.
If you want/need the movement, you will have to get a bag bellows if the rear element group is interfering with the bellows when you move things around. If that's not possible on the Intrepid, you'll probably need to get a different lens or camera, depending on which is more important; having all the movement available in the lens, or shooting with a 120mm-125mm lens more generally.
As for the dropped lens board... some cameras are built to center the lens on the axis tilt with a dropped board and others are designed to center the lens when on a centered board. I'd recommend getting the type of board that centers the lens properly because in most cases, the axis tilt will move with the rise/fall of the camera, so you can't center the lens on the tilt axis without using a proper board. Not that it is a huge problem, but it is a bit more intuitive to have the tilt axis centered on the lens properly. You can't really avoid refocusing after tilting either way, but it should require less adjustment if the lens is centered on the tilt axis.