I’ll just point to a reddit post about this one, from which I am mostly stealing the below: https://www.reddit.com/r/TheFarSide/comments/x39n7i/jw_miller/

“Staff and rod” are a Biblical reference to shepherding equipment and symbols of leadership, rest, protection, and love. As good an explanation as any.

“J W Miller” might be a reference to a 19th Century preacher, William Miller, who popularized the whole “calculating the Second Coming of Jesus Christ” doomsday thing, in later religious movements and doomsday prophecies. But I can’t find anything about having a “J” as part of his name.

Someone thought that Miller was also a reference to a boat building company, but this is the only one that came up on a google. I have no idea how popular the Miller boats are or were. But again, no “J” in the name here.

The boat might only be there to work in the “Rod == fishing rod” angle.

“J W Miller” might just be some random guy stuck in a biblical reference.