You can buy the standalone version of Lightroom 5.0 (which is the version sold on CD at Amazon and other places) and then use Lightroom without an internet connection. The Map Module will not work without an Internet connection.
You might want to download the latest update of Lightroom, which is Lightroom 5.7.1 and use that instead of Lightroom 5.0. You could download the installer file on a different computer from Product updates and then move that file to your PC which is not connected to the Internet and then install that way.
OK thanks. What's the map module?