I don't think this will work as you are thinking. Here's my experience:
They will only be available in full without a data connection if you either upgrade to premium and mark them as available offline and sync them before going offline. OR you do as suggested above and "print" them to a PDF format on your phone.
If you had a note open and then switched off your data connection that one note would probably still be fully available but I don't think the others will be.
But I haven't tested any of this, so if you really need something when you are offline, I'd suggest testing this all out in advance of actually needing it. If it turns out I'm wrong about how Evernote will perform, I'd love to hear that back here.