Indeed, they owned the houseboat together for many years, and operated it on the Sacramento delta. As I recall also, Jack mentions it in his autobiographical sketch in the Cunningham book. (By the way, that piece, only a few pages long, is a very interesting and revealing one; the information about his father and grandfather especially.)
It's often been remarked that the Sacto delta was the model for Trullion's fens and many other Vancian waterways and mudflats. To non-Californians: the delta of the Sacramento river and its tributaries extends from SF bay all the way to Stockton, and has hundreds of convoluted miles of waterways and numberless islets and inlets.
I read Dune serialized in Analog as a kid and loved it. It took the SF world by storm, for sure. The movie was bad (with some exceptional scenes). The Sci-Fi channel version was pretty good, except for the boring interludes between the action scenes. It seems overly portentious, to say the least, now; but still a good read.
I wonder if Jack talked the trade much with Poul and Frank. Remember, he says he only ever read one Anderson book; and Poul was a very close friend until his recent death.