I've been looking into Bill Bell's site. I haven't ruled out the Church book, just haven't gotten to buy it yet.
Bills site, http://www.ontheroadin.com/ , has nothing to do with Facebook folks. He does have a FB group where people can ask for up to date road info, but the bulk of his Mexico campground information is all located on a traditional site. He also used a Google maps overlay for all the locations.
Slight segway on to Facebook for a second. While the bulk of FB is mostly worthless, it is a good way to keep in touch with friends, and there are groups such as Bills that allow you to get good "on the ground" information about various things. If you are concerned about your personal privacy, don't put anything out there of a personal nature. Create an account using a dummy email address and don't post stuff about yourself. Also, don't click any of the ads or links. Pretty easy to not expose yourself while still gleaning some benefit.