You should get a phone with a data plan. So you can use the mobile version of everything. Annoying and slow, but far better than nothing. (And expensive, which is why I don't have one. >.>)
Why refuse to use it? If you were able to easily go online during this trip, and you just refused to anyway, I'd start calling you, and get the other to do so as well. So you'd end up having to use it anyway.
What, and shut yourself completely off from everyone you can tolerate? Think about it, you'll be on this trip with family. By shutting off the cell phone, you're cutting yourself off from both online and RL friends. You'll die.