Here are some resources and tips for using Chromebooks even without an internet connection. This is great for students who don't have internet at home, as well as a back up plan if your school network goes down.
Enable offline use of Drive/Docs: https://support.google.com/drive/topic/1628465
Example of backup plan for when network is down: have students write a paper or create a presentation. It will sync to their account when the Chromebook gets a network connection.
Chromebooks beyond the cloud: Everything Chromebooks can do offline: http://www.pcworld.com/article/2453999/chromebooks-beyond-the-cloud-everything-chromebooks-can-do-offline.html
Offline Apps. These apps work offline and then update when you get a connection again:
You can also go to the Chrome Web Store to find other offline apps: https://chrome.google.com/webstore/category/collection/offline_enabled
You can also download files when you have a connection and save them to the local disk drive to view later. PDFs work best. Students can download chapters from the online textbooks this way. You can also save and access files from a flash drive.
There are also apps that allow you to even save web pages to the local drive for offline access:
Read Later Fast - http://en.kioskea.net/faq/28746-read-later-fast-for-google-chrome
Pocket - http://getpocket.com/chrome/
There are also Android apps available for Chromebooks that can work offline (like Evernote)
See, Chromebooks aren't just "web laptops".