How do I start Gmail Offline without an Internet connection?
Yes you an start gmail without internet connection just as what the other said above but your mails will not be updated. You could also do it in your phone IF you have let your email remembered by your phone and checked "Always Log In"
Open a new tab in Chrome. There will be an icon for Gmail Offline. Just click it.
This, of course, assumes you've already installed the Offline Gmail app for Chrome. And enabled it.