A book like this is meant primarily as a vehicle to communicate ideas, and secondarily as a money-making exercise. There has to be a financial component, but the ideas are the driving force. If that's the case, I would encourage a free web content model, so that the most people are exposed to the writing and the ideas. The basic format, reviews of courses, lends itself to the web quite well, as independent articles or pages of which there can be thousands.
Unless there's regular updates, a subscription model online doesn't make sense to me.
IPad apps are a convenient way to monetize the e-content, and if the online presence has ads, buying an app that is ad free can be a moneymaker, too.
Supporting the money making I would look at physical and e-book companions. As you see above, there are plenty of people out there who want the hard copy.
In my pea-brained concept of the world, if you can get 10x, 100x, or 1000x people to see and read the material for free, that's 10x, 100x, or 1000x as many people who will consider purchasing the hard cover version, even if the rate at which they buy lags the rate of interested buyers buying if it is only available for a fee.
In the other part of my pea-brained concept of the world is that if you want to have your thoughts on golf influence how the masses think about the game, give the content away for free. If every google search for a rated course returns the course's site, golflink.com, golfnow.com, and doakguide.com, your writings will influence hundreds of thousands, if not millions of people.
DON'T STRANGLE YOUR BIG IDEAS BY USING A SMALL DISTRIBUTION CHANNEL. THINK BIG. CHANGE THE WORLD. GIVE THE ONLINE CG AWAY FOR FREE.
With enough people paying attention monetizing some of that stream will not hard.