For Facebook, you can handle the login portion of this with the Facebook Connect plugin: https://github.com/davejohnson/phonegap-plugin-facebook-connect/blob/m aster/README.md
Facebook also has a good bit of documentation to help you accomplish your goals of integration: http://developers.facebook.com/docs/guides/web/
Native device functions like Geolocation, Notifications, and Camera can be accessed using the PhoneGap API: http://docs.phonegap.com/
You can find other plugins that may help get your app to where you want it. To find them, I recommend just searching the web for "phonegap plugin" plus a one or two word description of what you want the plugin to do. (You might also search "cordova plugin" as well, to be sure you don't miss anything.) There is also a repository of many plugins here: https://github.com/phonegap/phonegap-plugins
As far as a CMS, you may want to look around for hosted solutions that are designed to work with mobile apps. A quick search yields a few services, such as Storage Room and Cloud CMS; there are likely many others out there. I have also heard of a few PhoneGap apps being built to serve content from a WordPress site, using the WordPress JSON API plugin. (Packt Publishing put out a book on using WordPress, FYI.)
By the way, you'll likely get the attention of more PhoneGap specialists by posting on the Google Group: http://groups.google.com/group/phonegap
Hope that helps you along your way.
