Offline WordPress Application

I think you should check for some other platform. WordPress is made to be live all the time : ) But if you are really keen in doing it in WordPress I can suggest a hard way of doing it. You can use the JSON-REST-API for WordPress and jQuery Mobile to build a mobile app that will run on any browser (not only mobile browser). Thank with cache manifest and localStorage you can preserve the information you want to be offline. But this is really a overkill so it is better to look for another platform.